Introduction

We recently published a major roundup of several high-end power supplies. As stated previously, such power supplies are already more than what most people will need, but for those looking to push extreme overclocking to new levels you might still need more power. We have eight 1000W power supplies we're looking at today the aim to provide just that. It's no surprise that power supplies in this range typically use high quality components, and the prices are also quite high. We have units from well-known companies as well as companies that are less familiar to our US readers.

As usual, we are testing with our Chroma programmable loads to load each rail to a specific amount. This is important to get truly accurate results and not merely approximate values. We conduct tests in two different temperature environments. One is normal room temperature of 25-26°C, while the second environment goes from room temperature and increases steadily up to 50°C. Especially during the higher temperatures, we will see how good the power supplies are and how well they can perform in high-stress environments. Components inside will perform much worse at higher temperatures, but we expect any good quality PSU to deal with such test conditions without failing.

Note: If you would like to know more about our testing methodology, equipment, and environment, please read our PSU testing overview.

Before we get to the test results, let's look at the various power supplies. Some of the units appear nearly identical, which is understandable as they are manufactured by the same ODM; others take a very different approach. While appearance, design, and features are all things to look at, at the end of the day what really matters with a 1000W PSU is how well it actually performs.

Akasa PowerMax 1000W (AK-P100FG)

The Akasa PowerMax is a newer name in the market, and their sales channels aren't well developed right now. Akasa first appeared in 2000, selling high-end coolers in Germany. After some initial success, other brands have pushed them into the background and their market share has decreased tremendously. The Taiwanese company is working to improve the situation by branching out into other markets. Today we will be looking at the PowerMax 1000W, which is also available in an 850W version. It comes in the trendy black we see from many other manufacturers, and it has a huge 135mm fan installed on the bottom side. Small hexagonal holes covered the rear of the unit in order to provide the best airflow possible. The power supply ships in a big carton box, and the unit and its long cables fit snugly.

The PowerMax has two large 12V rails rated at 35A. That will definitely be enough to cover even the most demanding graphics card and CPU setups today. The combined power of the both 12V rails is about 840W max, which is a fair amount of power. The input voltage is rated at 100 to 240VAC, but as usual we were able to run the power supply with 90VAC as well. Akasa states a 1000W peak power under 50°C ambient temperature, and we will verify this as part of our standard testing methodology.

The cable harnesses are very long and sleeved with black mesh. The 24-pin, 4-pin, and 8-pin connectors have a length of 75cm, which is the longest we have seen so far. People with full tower cases will appreciate the long cables since they will easily reach every corner inside the case. Smaller ATX cases might just feel cluttered with the longer cables, but most midsize ATX cases don't need 1000W power supplies.

The inside of the power supply looks very similar to the Silverstone unit, which isn't a big surprise considering both power supplies come from the same manufacturer. However, there are differences. A single transformer in the middle of the PCB handles the massive 12V output. The rest of the installed parts look very neat and are of good quality. The secondary caps are from Teapo, which we find in most PSUs today. Looking at airflow potential, we see some obstacles the air needs to get around. The shape of the heatsinks is well designed though and the air can go through without problems. The large sister PCB that has the input filtering stage could be in a better position, but it shouldn't be a problem. Unfortunately, the Akasa PowerMax didn't stand our 110% test; this isn't a deal breaker considering we are pushing the units beyond their rated capacity, but the fact that the similar Silverstone also failed this test indicates the design is at its limits.

Antec TruePower Quattro 1000W (TPQ 1000)

We tested the 850W version of this series in our last roundup and it performed very well throughout the test. Antec also sent us their 1000W unit to compare it to other similar units. As we mentioned before, the appearance of this particular design is unique with the racing stripe theme. That sets this unit apart from the "boring" black we see everywhere else, but for users without case windows none of this really matters. Antec is one of two companies with a single 80mm fan installed for cooling purposes; this is not necessarily a bad thing, as the internal design will determine whether this cooling is effective. 80mm fans are not necessarily louder than 120mm fans, but they do need to spin at higher speeds in order to move the same amount of air. The package is well made and you will find all necessary accessories for installing this unit.

The label isn't very different from the label of the 850W version. All the max outputs show the same values; the only difference is the max combined power of 840W here where we had 768W on the 850W unit. The combined power of the lower voltage rails of 3.3 and 5V is also 20W higher, which isn't much of a change.

The cable harnesses and connectors are the exact same as the 850W unit. There are eight SATA and nine Molex connectors, which provides plenty of choice for the end-user. However, as the 850W unit there are only three jacks for the peripherals, so you won't be able to use all 17 connectors. Still, it's nice for Antec to give users the choice of how many of each connector will be present. PCI Express graphics cards can be powered up with two 6-pin and two 6/8-pin PEG connectors, which is enough for a high-end SLI/CrossFire setup.

Even though the power supply is manufactured by the same company that builds the Akasa and Silverstone units, we see slight differences in the internal design. The heatsinks have a different shape, which is necessary given the different cooling setup that uses one 80mm fan. The heatsink is now thick and large, designed to work with the pull of the fan instead of the push method seen in other PSUs where the air blows at the heatsinks from below. The main capacitor is made by Hitachi, which is also a little better. It's not very often today that a company provides partial cable management and still uses an 80mm fan. The problem is the jacks at the back of the unit, which obviously block airflow. Antec manages to keep the jacks as low as possible so there is enough air coming through the front vents for good cooling. We will wait to pass judgment on noise levels, however.

Enermax Galaxy DXX 1000W (EGX1000EWL)

The Enermax Galaxy was one of the first real 1000W units in the market, introduced about two years ago. It uses a large 135mm fan on the bottom in addition to an 80mm fan at the back of the unit. We already tested this unit on a Chroma 8000 and it performed very well. We tested it again on our new Chroma and we generated similar results. Even though it is now the older statesman of the 1000W market, it can still show newer units a thing or two. The efficiency might be a little lower than newer models, but its stable DC outputs won't bring any complaints. The packaging for this unit is unique since it comes in some kind of sausage shaped container. (Ed: Or maybe Christoph just needs to eat dinner.) A little carrying strap would be a nice addition since the box is big, heavy, and not easy to carry with one hand.

The Galaxy 1000W comes with five 12V rails rated at 24A. As the label suggests, two of these rails have their own output and are separate from the other three rails. The total combined power of all the 12V rails is 900W. The 30A for the 3.3 and 5V rails is a nice addition but not much needed anymore.

For cables, Enermax seems to have the best choice possible. There are eight jacks on the front of the power supply, giving the user many connectivity choices. There are six cable-harnesses with 18 SATA connectors (three per harness) and six harnesses with 16 Molex connectors (four per harness). Five PEG connectors - three 6-pin and two 8-pin connectors - assure you will have plenty of options for future graphics cards. Enermax often has the Galaxy 1000W at trade shows with a huge number of hard disks attached, which is certainly one use for a 1000W PSU.

The housing is very long, and looking at the inside you can see why. Enermax uses this space for the huge heatsinks and the two transformers. The primary side carries two Rubicon caps, which is definitely a very good choice. The installation of an additional 80mm fan makes sense, as it ensures all the airflow moves in the proper direction. Otherwise, with the large chassis and fan on the bottom, the air might get caught in eddies and not cool as effectively.

Kingwin Mach 1 1000W (ABT-1000MA1S)

Kingwin sent us their Mach 1, a somewhat rare product these days since it still has numerous lights adding bling-bling. This is a fad from a few years back that most users no longer care for, but as with all fads there are some holdouts. It's interesting to see Kingwin's take on the lighted PSU market. The jacks on the front for the cable management have an acrylic ring around them. If you connect a harness and power on the unit, the ring will illuminate. This is mostly a useless function since it's difficult to see this when the power supply is installed in a case (even with a window), and it should also be readily apparent which sockets have cables attached. Still, it's different enough to warrant mention. The rest of the PSU looks sleek with a color scheme and fan that fit with the lighting.

This particular model comes with six 12V rails, four rated at 20A and two at 35A. The total combined power of the 12V rails is 960W (in theory), and the total combined power of all rails is just 10W more. So it should be possible to load the 12V rails very high, but only with minimal loading on the lower rails. In truth, six 12V outputs from only one transformer is a strange approach.

The cable harnesses are all sleeved with mesh as usual. The jacks in the back of the power supply have different pins sticking out which only allows the correct harness to be connected to the right jack. The Mach 1 has two 6-pin and two 6/8-pin PEG connectors for a decent SLI/CF setup. The 50cm cable length is okay but nothing special. Eight SATA and eight Molex connectors are also sufficient, but other units provide more options.

The heatsinks are flat and very thin. The incoming air through the bottom blows fresh air directly on the fins, which have enough space to let air reach the components underneath the fins. The flat structure may block some air or create unwanted turbulences, but we will wait for the temperature and noise testing to verify this. The primary cap is located in the middle of the PCB and made by CapXon. It's rated at 560µF and 400V at just 85°C.

OCZ ProXStream 1000W

OCZ has provided us with the ProXStream 1000W, which with a length of only 140mm is the shortest 1000W power supply currently available. It will fit it in cases the 220mm Enermax Galaxy can only dream of calling home. However, this short length brings a few other problems - if it didn't, we would see more of these units in the market. OCZ uses two PCBs inside the chassis, which is a good solution but not without problems. We will see later how this unit performs. The outside has a shiny mirror-finish coating and it is cooled by only one 80mm fan like the Antec TruePower Quattro. The packaging contains the power supply and concentrates on the necessary accessories.

The label doesn't make this very clear but there are four 12V rails, each rated at 20A. The combined power is 840W, which is slightly lower than many of the other units we're testing today. The unit is rated for 115 to 240VAC but as always, we tested it with 90VAC as well.

The cables are sleeved and the PEG harnesses are marked with a red mesh. There are four 6-pin PEG connectors, which is a bit unusual for a 1000W power supply; this is sufficient for most dual GPU setups, but two 6/8-pin connectors at least would have been a very good addition. Cables start at 45cm, which is fine for mid-tower cases but will not be enough for many larger cases. Considering the shorter chassis, it appears OCZ is catering to the mid-tower users that want a lot of power. How you're going to fit enough peripherals in a mid-tower case to make use of the available power is a question we will leave to the end-users. There are four harnesses for peripherals, two harnesses each providing six SATA and six Molex connectors.

As mentioned, the inside has two PCBs, which are then sandwiched together. They are actually stacked on each other and not facing each other as we have seen in other designs. The large plates cover and connect to all of the smaller heatsinks. This is necessary to help with heat dissipation, especially for the heatsinks that don't directly get sufficient airflow. The build quality is very good but all of the components still need air to cool down. Since cooling is provided by a single 80mm fan, heat dissipation needs to be a primary consideration.

Silverstone Strider 1000W (ST1000-NV)

Silverstone sent us their Strider 1000W unit, which comes with detachable cables. Users can detach all of the cables, including the 24-pin ATX harness. This makes sense as Silverstone also offers a complete set of shorter harnesses for smaller cases. The housing is a standard black and cooling comes from a large 135mm fan. Since the PCB for the cable management takes some extra space, the Silverstone is longer than the Akasa PSU. The Strider 1000W comes in a huge package with maximum protection on all sides - expensive but a good way to prevent losses caused by shipping. Silverstone includes all the necessary parts for a quick installation.

The label shows the same rated values as the Akasa. The 12V rails are 35A each and the 3.3 and 5V rail have a combined power of 200W, which is plenty for today's systems.

All cables are nicely sleeved, as expected for any high-end power supply. PCI-E harnesses have a small sticker attached, which clearly states their purpose of powering up graphics cards. There are each six Molex and six SATA connectors - average for this roundup, though a few more wouldn't be bad. The max length of the peripheral connectors is 95cm for the SATA/Molex and 105cm for the two floppy connectors.

Other than the different main capacitor from Nippon Chemi-Con, there is almost no change at all from the Akasa model. The modular cable design is the only other difference. The use of a better capacitor in the primary parts is greatly appreciated, but as mentioned in the Akasa overview, the Strider power supply didn't make the 110% test and just stopped operating while applying the load. It worked fine right after the failure, however, which at least shows they have a very good OPP. A power supply doesn't need to deliver 10% more than stated on the label, and we perform this test only to see how much more power we can expect over the rated output.

Thermaltake Toughpower 1000W (W0132RU)

Thermaltake power supplies are often quite nice to look at, and the bronze palette fits nicely with the red of the button and the cover for the coils. The power supply is quite long - we'll find out why in a moment. One thing that perplexes us is the fan-grill for the large fan on the bottom. Thermaltake punches holes in the casing, making the use of a separate grille unnecessary. The problem with this method is the decreased amount of air that can pass through the holes. If you compare a normal fan-grille to this one, it is obvious the standard fan-grille will allow for better airflow. To compensate, it may be necessary to run the fan at higher RPMs, which is not something most people desire.

The label is quite different from what we are used to with other power supplies. This has something to do with the fact that there are in fact two power supplies inside the chassis. We will see this when we open up the unit. The left side shows two 12V rails with the 3.3V rail together and a maximum combined power of 500W. The right side shows two 12V rails and the 5V rail together with a maximum of 500W as well. Together that is 1000W. Each of the 12V rails is equipped with either 20A or 36A. The 36A on each side will be useful for the highest-end graphics cards.

Thermaltake includes a vast amount of cable harnesses as can be seen in the shot above. There are six PCI-E connectors - three 6-pin and three 6/8-pin. The length varies from 45 to 60cm. There are four additional peripheral harnesses, providing six Molex and six SATA connectors in total.

Now comes the interesting part. As we can clearly see, there are two separate power supplies inside the housing. Each one has its own PFC stage, transformer, and secondary stage with all solid capacitors. This means each part shares only the input filtering stage. We saw this topology with the PC Power & Cooling Turbo Cool 1200W and the performance was very good. The only problem was the lack of airflow through the power supply, and we will see if Thermaltake fares better in this regard. PC Power & Cooling used two separate PCBs, vertically mounted on the main PCB. Thermaltake took a different approach and installed two circuits on one PCB. The advantage of the Thermaltake design is better cooling for the components. The fan blows directly at the components and heatsinks.

Ultra X3 1000W

The Ultra X3 is another older power supply; which is reason enough to include it in our roundup today. We can see if the newer models offer improved performance, or if they're merely newer. The X3 has a very nice mirror-finish coating and a large 135mm fan installed on the bottom. The back has plenty of perforations to serve as the exhaust. The packing is unusual in that the PSU is placed in the middle of the box between two massive sheets of foam, which makes it nearly impossible to damage the inside during transport. We are surprised more companies don't take this approach, particularly on expensive high-end models.

A single 12V rail is something we see on occasion, but this does not follow the latest PSU guidelines. The 12V rail provides up to 70A. The 3.3V rail has 24A and the 5V rail has 28A, which is enough for today's usage. This power supply is also rated with just 115 to 230VAC, but again we were able to test with 90VAC.

The cables are flat, with the wires running together similar to what we see with flat IDE cables. Ultra definitely has an eye-catching design with this approach, though the first company with these cables was Corsair. The length of the 24-pin, 4-pin, and 8-pin connector is only 40cm, which is really quite short. The X3 has four 6-pin and two 8-pin PEG connectors, though users can only connect four at the same time. The PEG lengths of 45 and 50cm is enough for medium size cases.

A look inside shows us two thick heatsinks without many fins on the sides. There is one large coil on the primary and two transformers in the middle. The caps in the secondary side are made by Teapo. Since the heatsinks don't have any large fins to the sides the air can travel nicely through even to the bottom of the PSU to cool each components attached to the PCB. The airflow is also very good since there aren't many obstacles in the way. Usually, however, larger heatsinks are used to provide a greater surface area and improved cooling performance; whether Ultra's approach will work as well as the more traditional designs remains to be seen.

Product Comparison: Loading Charts

All of the power supplies we are testing today are rated at the same 1000W, but they have differing amounts of 12V rails. That along with voltage drop as we increase the load results in slight differences with our load tables, but there's nothing particularly noteworthy. Here are the settings we used throughout testing.

Akasa PowerMax
PSU Load	3.3V	5V	12V1	12V2	Total Wattage
10%	2.04	2.45	3.32	3.32	101
20%	4.08	4.89	6.64	6.64	201
50%	10.19	12.23	16.59	16.59	497
80%	16.31	19.57	26.54	26.54	787
100%	20.38	24.46	33.18	33.18	975
110%	22.42	26.91	36.49	36.49	1071

Antec TruePower Quattro
PSU Load	3.3V	5V	12V1	12V2	12V3	12V4	Total Wattage
10%	2.54	2.12	1.66	1.66	1.66	1.66	99
20%	5.08	4.23	3.32	3.32	3.32	3.32	197
50%	12.69	10.58	8.29	8.29	8.29	8.29	493
80%	20.31	16.93	13.27	13.27	13.27	13.27	789
100%	25.39	21.16	16.59	16.59	16.59	16.59	986
110%	27.93	23.27	18.25	18.25	18.25	18.25	1085

Enermax Galaxy
PSU Load	3.3V	5V	12V1	12V2	12V3	12V4	12V5	Total Wattage
10%	2.14	2.14	1.33	1.33	1.33	1.33	1.33	102
20%	4.28	4.28	2.67	2.67	2.67	2.67	2.67	203
50%	10.71	10.71	6.67	6.67	6.67	6.67	6.67	500
80%	17.14	17.14	10.67	10.67	10.67	10.67	10.67	787
100%	21.42	21.42	13.33	13.33	13.33	13.33	13.33	971
110%	23.56	23.56	14.67	14.67	14.67	14.67	14.67	1062

Kingwin Mach 1
PSU Load	3.3V	5V	12V1	12V2	12V3	12V4	12V5	12V6	Total Wattage
10%	1.55	1.93	0.93	0.93	0.93	1.62	1.62	0.93	101
20%	3.10	3.87	1.86	1.86	1.86	3.25	3.25	1.86	201
50%	7.74	9.67	4.64	4.64	4.64	8.12	8.12	4.64	497
80%	12.38	15.48	7.42	7.42	7.42	12.99	12.99	7.42	785
100%	15.48	19.35	9.28	9.28	9.28	16.23	16.23	9.28	971
110%	17.03	21.28	10.20	10.20	10.20	17.86	17.86	10.20	1064

OCZ ProXStream
PSU Load	3.3V	5V	12V1	12V2	12V3	12V4	Total Wattage
10%	1.72	1.85	1.74	1.74	1.74	1.74	101
20%	3.45	3.69	3.48	3.48	3.48	3.48	202
50%	8.62	9.24	8.71	8.71	8.71	8.71	502
80%	13.79	14.78	13.93	13.93	13.93	13.93	796
100%	17.24	18.47	17.41	17.41	17.41	17.41	990
110%	18.96	20.32	19.15	19.15	19.15	19.15	1090

Silverstone Strider
PSU Load	3.3V	5V	12V1	12V2	Total Wattage
10%	2.04	2.45	3.32	3.32	102
20%	4.08	4.89	6.64	6.64	204
50%	10.19	12.23	16.59	16.59	503
80%	16.31	19.57	26.54	26.54	788
100%	20.38	24.46	33.18	33.18	973
110%	22.42	26.91	36.49	36.49	1080

Thermaltake Toughpower
PSU Load	3.3V	5V	12V1	12V2	12V3	12V4	Total Wattage
10%	2.13	2.13	1.20	2.16	1.20	2.16	101
20%	4.26	4.26	2.40	4.32	2.40	4.32	202
50%	10.66	10.66	6.00	10.79	6.00	10.79	498
80%	17.05	17.05	9.59	17.27	9.59	17.27	787
100%	21.31	21.31	11.99	21.59	11.99	21.59	976
110%	23.45	23.45	13.19	23.75	13.19	23.75	1070

Ultra X3
PSU Load	3.3V	5V	12V1	Total Wattage
10%	1.73	2.01	6.90	101
20%	3.45	4.03	13.79	202
50%	8.63	10.07	34.48	498
80%	13.81	16.11	55.17	785
100%	17.26	20.14	68.97	971
110%	18.99	22.15	75.86	1063

Product Comparison: Cable Lengths

When it comes to ATX cables lengths, we find different approaches from the manufacturers. As we can see, Akasa equips its PowerMax with 75cm cable harnesses - sufficient for even the largest cases. Next in line are Enermax and Silverstone with up to 60cm harnesses. The average length of 50cm is reached by Antec and Kingwin. Ultra, OCZ and Thermaltake power supplies only have 45 to 50cm harnesses on disposal. This seems quite short but it depends on the case you will use. For most cases, a 50cm harness will be more than enough, and in some cases shorter cables would even be desirable - that's why Silverstone also sells a short cable harness package (not tested or shown).

Having a 1000W power supply means you likely bought it to power up many hard disks, two or more high-end graphics cards, a quad-core processor (or perhaps dual socket octal-core) - perhaps all of these combined. Here we have different approaches from the manufacturers. Ultra and Thermaltake deliver the best choice of cables with their cable management, since they include six PEG harnesses and allow the users to select which ones are most useful. The downside is that you are only able to connect four at the same time, but who needs six PEG connectors? If you're moving to an all-SATA setup, it's also good to be able to ditch unnecessary Molex connectors.

Enermax has the best connectivity since the user will be able to connect up to five PEG connectors at the same time. With the Galaxy, you will have three 6-pin and two 8-pin PEG connectors available. Akasa has only four 6-pin connectors like the OCZ ProXStream but at least you can change two of the connectors to 8-pin PEG connectors. Antec and Silverstone will work with any dual graphics cards user with the two 6-pin and two 6/8-pin PEG connectors - or quad GPUs provided each GPU only needs a single PEG connector.

Product Comparison: DC Outputs

We have to say we are quite impressed by all of the units for having such a great and stable power delivery throughout testing. As usual, all of the units start above 12.00V, but even when delivering 500W of power the 12V rails are over 12.00V on more than half of the units. At full load, some of the power supplies are starting to drop off rapidly, though all remain in spec. The OCZ ProXStream shows its full potential by delivering a stable output of 11.92V at 100% load, which is just a little less than the optimal amount.

With the lower voltage rail of 5V, we see similar results as the 12V rail. The units have no real problems distributing up to 100% of load. Coming to these high loads for 1000W PSUs is getting more and more difficult for the power supplies but as we can see all of the units are still inside specifications.

With the 3.3 V rail we see three power supplies coming close to the lower end of the specified range. Remember, the lowest "allowable" value is 3.14V, and 3.16 or 3.17 are quite close to that amount. As the results show, the OCZ is again on top of the others and even under high load delivers a stable 3.24V - quite impressive.

Product Comparison: Voltage Ripple/Noise

For voltage ripple/noise testing, we conducted measurements at three load levels (20%, 50%, and 100%). The top row contains the ripple results on the 3.3V, 5V, and 5VSB rails and the bottom row contains the 12V rail(s). We have to confess that we broke the Kingwin unit when we dismantled it (Ed: Note to readers - don't try this at home!), and afterwards we discovered some issues with our initial ripple testing. We are thus unable to include ripple results for that unit.

Akasa PowerMax 1000W (AK-P100FG)

Antec TruePower Quattro 1000W (TPQ 1000)

Enermax Galaxy DXX 1000W (EGX1000EWL)

OCZ ProXStream 1000W

Silverstone Strider 1000W (ST1000-NV)

Thermaltake Toughpower 1000W (W0132RU)

Ultra X3 1000W

Akasa has a very nice output quality of just up to 8mV on the 12V rails. The Enermax Galaxy at lower loads shows just around 4mV on all of the 12V rails, and with higher loads of 1000W we measure just 18mV tops. OCZ's outputs don't rise higher than 10mV on the lower voltage rails and up to 20mV on one of the 12V rails. The Silverstone Strider has clean output of just up to 8mV at full load. The best quality shown today comes from Ultra where we measured not more than 2mV at any load on the 12V rail; the lower voltage rails have no more than 12mV. Overall, the power supplies all provide very nice and clean output.

Product Comparison: Efficiency

As 1000W are nothing to play with we expect all of the tested units to have a higher than average efficiency. The efficiency curve shows exactly that with all power supplies reaching 84% to 87% efficiency. We tested the 850W version of the Antec TruePower Quattro last time and we saw similar results with 87% at 230VAC. Enermax, Ultra and Thermaltake show the lowest results of 84%, which is still very good. The majority of power supplies perform reach up to 86% efficiency at loads of 500W.

Product Comparison: Acoustics

The acoustic graph shows more distinct results than the efficiency graph. We have many low noise power supplies and Akasa seems to be the lowest one. With a stable 19dB(A) throughout the test it's quite amazing, but it makes us think: if your fan doesn't start turning faster your power supply will most definitely get hotter inside. Looking at the green line of the similar Strider power supply, the fan starts to turn much faster at 700W and therefore cools the inside better. All other power supply perform reasonably well with noise levels under 24dB(A) most of the time. Only the OCZ ProXStream sticks out from the mass again, this time in a negative fashion. With normal operation starting at 35dB(A) and increasing to 45dB(A), this power supply never get silent and can end up quite loud. The Ultra X3 and Enermax Galaxy - and to a lesser extent the Enermax and Kingwin - start out quieter but above 500W begin to increase in volume quite rapidly.

Prices and Conclusion

All of the power supplies we're looking at today perform quite well, so for many the deciding factor is going to be price and availability. Half of the power supplies carry similar prices, but there are some standouts. The high exchange rates from the EUR to the US$ can cause some concerns for certain people, however. Take the OCZ ProXStream: about 225 EUR in Germany and around $250 in the US, which at present works out to US$330! Perhaps the best thing for our European readers right now is to book a flight to the US.

The US prices look quite different from the Europeans. In the US, we can recommend almost any PSU worth spending the money on. We recommended the Antec TruePower Quattro 850 in the last roundup and the Holiday Buyer's Guide as we have seen very good performance for a relatively low price. The 1000W unit brings a little more power with it but the difference is small enough that we recommend buying the 850W version for most people - the extra 150W will only be necessary in extreme situations.

The Akasa PowerMax showed good results today and has very long cables. It is unfortunately not available in many shops at present, but the company is working to address that. In Europe, you can get it for 198 EUR at komplett.de. Performance-wise, the OCZ ProXStream stands out today with stable DC outputs, low ripple, and high efficiency, but also with high noise levels. If you're not ultra concerned with noise levels, the ProXStream is a great deal at $230-250. It also has a very small form factor which will let it fit into every standard ATX case.