Introduction, Package Contents, and Specifications

Today we continue with the second part of our series of 750W power supplies. The Corsair TX V2 is the second 80 Plus Bronze certified PSU with non-modular cables that we're looking at for this range. Corsair might be a leading manufacturer of RAM modules and SSDs, but power supply quality depends largely on the ODM and their design. The big question of the PSU source is easy to answer. Seasonic is the company behind many Corsair products—and they're definitely a good choice, much better than using CWT like the original TX750—but what about the internal design and components?

Corsair's TX V2 750W includes a power cord for the American power grid, four screws, one Corsair sticker (for your case), and a manual. The latter is more like a warranty agreement than a helping hand. There is an installation guide, but the warranty part shows some interesting limitations. "[Corsair] shall not be liable for any special, incidental, indirect or consequential damages [...] including [...] loss of profits, revenue, or data." So the 5-year warranty won't help you, other than getting a new PSU should the TX750 go belly up. Don't worry, though; these are common terms and are present with nearly every PSU.

While if it is not stated directly anywhere, the sticker indicates Corsair is using a single rail for +12V. We'll see later that this is not the case, so we'd like to see Corsair list both 12V rails on their sticker to avoid confusion. 744W combined power also indicates this is another PSU with DC-to-DC VRM. +3.3V and +5V are rated at 25A each and should be able to provide enough power for HDDs/SSDs and/or other peripheral components. 3A on +5VSB is also relatively strong.

Corsair uses a 140mm fan from Yate Loon with a ball bearing. The product number is D14BH-12 and it takes 0.70A. A Sanyo Denki fan would be better but the price could be a problem and Sanyo Denki is still a reason to buy the more expensive Corsair AX. Corsair differentiates between the two lines by modifications such as this, which helps them reach lower cost markets.

Appearance, Cables and Connectors

Like the Corsair AX 750W, this model has a simple black finish. On both sides of the PSU there are Corsair logos with the product name. With a usual fan grille and a small power switch it looks "boringly normal" in contrast to Antec's HCG series. The surface is scratch-resistant and those honeycombed ventilation holes at the back are relatively small, which is good for EMI shielding but may hinder airflow slightly.

Corsair has a nicely fashioned hole for the cables exiting the casing, which will protect the black sleeving and cables against damages from rubbing against the case. Cheap power supplies often have sharp-edged outputs that can destroy the sleeving or in some cases even damage the wires, so the protective cover around the edge is appreciated.

The TX750 comes with a large number of fixed cables. You'll want to make sure that your case has enough space to store unused cables, so you don't obstruct the airflow. If your case has a window, the fixed cabling can also look untidy, which is why most users with windows cases prefer modular cables.

The Corsair TX750 V2 has fewer SATA connectors than the Antec HCG 750W, though the length of both mainboard cables (24-pin and 4+4-pin) are equal. Like Seasonic, Corsair offers an FDD adapter in case you need it. In total, the TX750 supports eight SATA and eight Molex connectors, which is more than enough to support most PC configurations. This PSU is also SLI and CrossFire certified.

Internal Design and Components

The interior has many indicators that this is a Seasonic-made power supply. First, there is only one DC-to-DC PCB for +3.3V and +5V instead of two. We saw this in the M12D 850W. Furthermore, the filtering behind the entrance is almost identical to the S12D design.

Interesting to note are the two different solder points for +12V. At one point we can find yellow and black cables and a "12V2" silkscreen on the PCB—just like the S12D design. That means this isn't a real single-rail PSUm and in fact most PSUs aren't multi-rail designs. Instead, they share the current between more than one output rail. That makes the design a modern version of the S12D layout. The heatsinks are smaller and the main caps as well as the DC-to-DC VRM are displaced, but otherwise they're very similar.

Transient filtering starts behind the AC inlet and continues on the mainboard. There are two X-capacitors, three coils (one is a current-compensated version), and six Y-capacitors. Six caps sounds very helpful here but we have to keep in mind that the leakage current on ground shouldn't get too high. Otherwise, we get a "dirty ground" contact that can create issues; remember that EMC doesn't necessarily equate with safety. You'll want to look at the impedance of the disturbing source, the type of problem, and the input characteristics of your power grid to choose the right components. Quantity can only be effective in combination with precision. Ultimately, having six Y-capacitors isn't a guarantee that a PSU is good PSU, but they are very good against common mode interferences. Let's move on to the power factor pre-regulator.

Here we find two GBU806 (GBU case, 8A forward) for rectifying and two very large Rubycon caps. Like nearly all modern PSUs, the TX750 has active PFC. All transistors have very common ratings so there is nothing special needed to reach 80 Plus Bronze. In the secondary circuit we find the usual five diodes in a TO-220 housing. Again there's no need for anything unusual like synchronous rectifying. The controlling circuit, incidentally, is located at the bottom of the picture, which is another modification of the M12D design. Some of those larger capacitors lean but most components are fixed well.

Voltage Regulation

All the rails fall clearly within ATX specifications. They start slightly over the target voltage and end with results close to 0%. Since this PSU has two 12V outputs, we selected the worst rail for the tables (which is our standard procedure). +12V shows the best regulation, and will have no trouble with higher voltages. -0.08% at overload is one of the best results we have seen.

Ripple and Noise

Both smaller rails have less than 30mV ripple and noise, making this PSU is as good as the Antec HCG if not better. +12V has higher absolute ripple, but it's actually closer to spec as a percentage. All of the rails are far away from the limit. The TX750 V2 can't beat the Corsair AX 750W, so we now know why there is such a high price difference. Of course 80 Plus Gold is another reason to buy an AX-series PSU.

Noise Levels

The TX750 won't be a great fit if your goal is to create a silent or near-silent PC. On the other hand, the higher noise levels generally correspond directly with airflow, so this PSU should help reduce temperatures in your PC, which is especially important for SLI or CrossFire setups. We would still like to see less noise at low loads, since 75W output means there shouldn't be much heat to deal with. As usual, the fan rotates at full speed during overload and is close to 40 dBA. Most computers should not reach this level, but it is good to know that this PSU is still not the loudest one—we have seen worse results on other PSUs.

Efficiency and PFC

Note the difference the power grid makes.115VAC means higher current and more stress for all power supplies, while 230VAC shows a worse power factor at all loads. Nevertheless, 0.890-0.975 PFC is very good and most users will find 86-88% efficiency more than sufficient. While it doesn't quite make 80% efficiencey at 10% load, it is a good 80 Plus Bronze PSU for sure. With a low input voltage power factor is always over 0.90.

A Good Buy, But Not a Single-Rail PSU

Looking at our measurements, we see that this is a very well-regulated PSU with moderate ripple and noise results and a strong (but noisy) fan. Comparing the ratings on the label with reality, we have to mention the wrong documentation for the +12V rail; this is in fact a multi-rail design. There are two different solder points and there is no direct connection between those rails. Sometimes there is a big wire on the back of the PCB to create a single-rail where multi-rails was planned, but we can find nothing to suggest that is present. Thus, Corsair has two rails, just like the original S12D design that serves as the basis for this PSU.

The package includes all the important accessories for installation and a user guide. Like the previously tested Antec HCG 750W, the Corsair TX V2 750W uses fixed cables. All the cables have lengths of 60cm or more, so this PSU will work well in larger cases. It includes four 6/8-pin PCIe connectors and 16 peripheral connectors (8 SATA + 8 Molex), plus an FDD adapter (15cm). The black cable sleeving is better than the cheaper version where you still can see every single cable. Moreover it looks very nice and fits with the black finish of the case.

Internally, Corsair implemented a well-equipped filtering stage against emission from the conductors. Furthermore, the case has a good shielding. Corsair uses well chosen capacitors from Nippon Chemi-Con and Rubycon. There is a lot of glue inside, but glue is a good and cheap solution for stabilizing components. The PSU has active PFC, all the important safety functions, and not least DC-to-DC VRM with all solid capacitors. All other parts have components from reliable sources.

The TX750 doesn't need active rectifying with modern transistors to reach 80 Plus Bronze. Even so, the efficiency is relatively high with 76-86% at 115VAC and even better 81-88% with 230VAC. (If you only run at 20% loads or higher, minimum efficiency climbs to 83%/84% for 115VAC/230VAC.) Considering the good efficiency, the fan could be quieter, particularly at low loads. 24 dBA is too high for 10% load when other manufacturers are able to stay under 20dBA with low temperatures.

The Corsair TX V2 750W may not be the greatest in all areas, but it does have some advantages over the competition. The voltage regulation is excellent, with all rails starting at less than 1% overvoltage and landing very close to 0% at overload. The current online price of $105 ($95 after $10 mail-in rebate) makes the Corsair TX V2 750W affordable and puts it near the top of the "budget" 750W list, even with all the opponents it has to face. Antec's HCG 750W has great components and performance as well, but the price and ripple results are higher. The PC Power & Cooling Silencer 760W is another strong competitor, but the price is higher ($110 after rebate; $130 otherwise). The design is almost the same as well, since the PCP&C is identical to the older Seasonic S12D while Corsair is using the improved version.

Overall, the Corsair looks to be the best of the less expensive 750W PSU offerings right now, and it's a definite improvement over the original TX750. If you want to buy an 80 Plus Gold model with a good fan, the Corsair AX750 is still better, but you're looking at $160 for the slight improvement in results—definitely a case of diminishing returns. If 80 Plus Bronze certification is sufficient for your needs, and you don't mind the fixed cables, the TX750 V2 is a good buy. Let's hope Corsair can bring this quality into lower rated power supplies as well.