We've also seen a recent flurry of high-end motherboards announced with a new form factor, WTX. The "W" in WTX stands for workstation, but many of these cases and motherboards will be targetted at the server market.

Basically, WTX is a major extension of ATX, but the big features of WTX include a larger motherboard for greater expansion and enhanced power capabilities that ATX could not provide sufficiently for the workstation market. The larger motherboard makes more room for integrated components on the WTX I/O shield and optionally two additional expansion slots. The enhanced power capabilities are designed to support multiple processors, AGP Pro graphics cards and lots of hard drives. WTX cases are backwards compatible with ATX motherboards, but not vice versa.

The WTX specification has actually been in the works for quite a while, but is just now showing up in motherboard and case products. The first WTX case to make it to the AnandTech labs is the Addtronics W8500, graciously provided by Computer Nerd. They sell the W8500 under the "POW!er Pro Tower" label for $265.

You may not have heard of Addtronics, but there's a good chance you've worked with or at least heard about an Addtronics case without even knowing it. Remember the Supermicro SC750-A? Addtronics designed and produced that case for Supermicro. Supermicro is actually the OEM buyer in this situation and many other "Supermicro" cases are also designed and built by Addtronics.

So what happens when you give Addtronics the chance to work with a brand new form factor designed for the workstation/entry-level server market? A Supermicro SC750-A on steroids? Or would there be bugs with the new form factor? Let's find out...

Design

In many ways, the Addtronics W8500 has a very similar feel to the Supermicro SC750-A. However, this comes is not a huge surprise since the SC750-A is nothing more than the Addtronics EX-6890 with a few minor modifications and the Supermicro label slapped on the front. This time around, the Addtronics has taken a different route to achieve massive expandability. The W8500 stands 6 inches shorter than the behemoth SC750-A/EX-6890, but is 3 inches wider and 1 inch deeper. To ensure this thing never tips over, four large, height adjustable feet are attached to the bottom of the case. A set of casters, or wheels, is optionally available to make the task of moving this monstrous case around a bit easier.

Following a similar design philosophy as used in the SC750-A/EX-6890, the front bezel simply snaps into place and features a mechanical locking mechanism to prevent unauthorized entry to the system. Plenty of ventilation holes allow for excellent airflow into the front of the case. The back of the bezel features a washable air filter that prevents the uptake of dust into the case - a serious issue for a machine that runs 24 hours a day, 7 days a week.

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The power switch is located in the upper left hand corner and is large enough to press easily. The rest button is just below the power switch and is quite a bit smaller, but still easy to press. Exposing its server roots, the W8500 features a grand total of 6 status LED's - 4 separate red HDD LED's, a green power LED, and a yellow overheat LED.

Once a rear panel cover is removed, the first evidence of the WTX form factor can be found. The ATX I/O shield opening is replaced by the wider WTX I/O shield in accordance with the WTX specification. Further, a grand total of 9 expansion slots are now available thanks to WTX, with the two additional slots tacked on to the left side of the motherboard.

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Opening the W8500 is much like opening the SC750-A; simply tug on the bottom of the bezel to release it, then remove three screws to free each side panel. The side panel then swings out on "hinges" at the rear of the case. Once open about 45 degrees, the panel can be lifted slightly to complete the removal process. Thanks to the way in which the bezel snaps to the front of the case and a small lip on the side panel, it is not really necessary to use screws to secure the side panels if quicker entry is desired. The design and construction quality of the case allow all panels to be removed and replaced with minimal effort. Not surprisingly, the build quality is equally as good once inside, with no sharp edges and solid construction.

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One of the advantages of size is that there's more room for expansion and the W8500 does not disappoint with its grand total of 11 drive bays. That includes 5 external 5.25", 1 external 3.5", and 5 internal 3.5" drive bays, which are all located at the front of the case.

External 5.25" devices are mounted in one of the 5 available bays via a simple rail system, very similar to the one used in the original SC750-A and still used on the Addtronics version, the EX-6890. Simply attach the rails to the drive with screws and slide into place. Finally, a single screw on each side secures this assembly to the main chassis. Also worth noting is the fact that the drive rails can be secured in the drive bays, even without a device installed. That way, you'll never have to worry about looking for drive rails when adding additional devices. It actually ships this way from Addtronics - a very nice touch as far as we're concerned.

Attaching a floppy drive to the sole external 3.5" bay is a piece of cake; removal of just one screw is required to release a small bracket to which the floppy drive is attached. The 5 internal 3.5" bays are more conventional, as drives simply slide into place and are attached via screws directly to the chassis.

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Motherboard Installation

One of the other big advantages of such a large case is the ease of motherboard installation. In the case of the W8500, this is even easier thanks to a removable motherboard tray. That tray is attached via three screws that are inserted from the rear of the case. A handle allows easy removal of the tray once the screws are removed. Traditional metal standoffs are screwed to the tray and the motherboard is then screwed into the standoffs.

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Our test bed ABIT BX6 Revision 2.0 fit with tons of room to spare (below and left), as expected from a server case of this size that was designed to hold much larger extended ATX boards. At 21 inches deep, there was plenty of room to work with, even with a full extended ATX motherboard installed.

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For comparison purposes, a WTX motherboard is pictured to the right above. Notice the additional width of the board adjacent to the I/O ports. This particular motherboard, an IWill i840 sample did not take advantage of the optional extra expansion slots afforded by the WTX form factor.

Power Supply & Cooling

Despite being a WTX case, the base power supply option for the W8500, and the one equipped on our sample, is the 300W ATX 2.01 compliant CWT-300ATX from Channel Well Technology. While Channel Well isn't exactly a household name, we found that this power supply was actually internally identical to the Antec PP-303X. Externally, the Channel Well version actually lists a higher combined rating on the +5V/3.3V rails - 160W vs. 150W. The PP-303X is on AMD's Athlon Approved Power Supply Listing and turned out to be the most stable performer in our AMD Athlon Buyer's Guide - Part 4: Power Supplies. Remember, our sample came from Computer Nerd, but other distributors may substitute other PSU units or even sell it without one at all.

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A temperature controlled 80 mm fan exhausts air out the back of the PSU in accordance with ATX 2.01 specifications. Air is drawn in from the bottom of the power supply, standard for an ATX model. Although the unit is mounted within a large metal bracket that largely blocks these intake holes, we did not notice any major adverse affects to this setup. Of course, it doesn't hurt to have a number of other fan mounts to keep the system cool and that's exactly what the W8500 does.

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Cooling is of course critical in a server environment and Addtronics has shown us in the past that they knew what they were doing with the EX-6890. This time, a grand total of 9 fans can be installed in the W8500, with virtually every hot component of the system targeted by one or more fans. Four 80mm fans can be mounted right next to the CPU and exhaust all the heat generated by virtually any CPU configuration. Only one of these fans comes preinstalled from the factory.

A bracket in front of the internal 3.5" bays holds a big 92mm fan that is configured to bring in cool area through the bezel and blow it right over the hard drives. This fan is also a standard feature on the W8500. In the past, we've found this configuration to be excellent for keeping hot drives cool. Right next to that fan is another 80mm intake fan, while two more 92mm intake fans are positioned at the bottom front of the case. Finally, an 80mm fan mounts to the side of the 5.25" drive bay and is fed air from vents in the left side panel.

The Test

For full details on how we tested, please read AnandTech's case testing methodology.

Our Addtronics W8500 evaluation sample featured a 92mm intake fan mounted in front of the internal 3.5" bays and an 80mm exhaust fan at the rear of the case, adjacent to the CPU.

Maximum sustained temperatures were very close to the other cases we've tested in this class, the Supermicro SC750-A and the Enlight EN-8950, both excellent cases in all respects, but especially as far as cooling goes. Ambient temperature was identical to the SC750-A and a few degrees higher than the EN-8950. CPU temperature was also right in line with the Enlight, even though that case features 2 exhaust fans adjacent to the CPU. Once again, we've found that a good heatsink and fan make the biggest difference as far as CPU temperature goes. Finally, with a fan directly on the hard drive, the W8500 was a full 5 degrees cooler than the Supermicro and 7 degrees cooler than the Enlight.

Once again, CPU temperature has generally shown to be most dependent on having a high quality heatsink and fan in AnandTech's testing.

Going by average temperatures alone, the W8500 was the coolest overall case we've tested so far - in any class. This includes beating out the Supermicro SC750-A and the Enlight EN-8950 Server Case, both excellent cases in all respects, but especially as far as cooling goes. And the best part about it is that the W8500 still has room for 7 more fans.

Conclusion

If you've got one of the first WTX motherboards on the market and are looking for a high quality case to house it, look no further than the Addtronics W8500. It's one of the few WTX cases on the market at this point in time, excels at cooling, and has great expandability - all without any major flaws. At almost $300, the price seems a bit hefty, even for the intended audience, the entry level server market.

Nevertheless, even if you don't need a WTX form factor case right now, the W8500 could potentially be a slightly more "future-proof" investment than a standard ATX case. We don't expect the entire motherboard industry to transition to WTX as its intended for servers and high-end workstations. It offers no benefits for most OEM's that are interested in higher volume markets. However, the benefits for the high-end market are many, and many of the upcoming i840 motherboards will be WTX.