I was a bit surprised to see some differences between the two power supply systems, but the true results will come with real-world testing. I will be testing each power supply in my dedicated test system, which consists of the following hardware.
Intel Core 2 Duo E6600 @ 3.5 GHz
Ultra Products ChillTec Thermo Electric CPU Cooler
EVGA 680i SLI Motherboard
Two 8800 GTX cards in SLI configuration
2 Gb Corsair XMS PC2-6400 Memory
74 Gb Western Digital Raptor 10k RPM HDD
Lite-On Optical Drive
HighSpeedPC Tech Station
I used a digital multimeter to obtain voltage readings. Since most power supplies correct any fluctuation in the current to the rails before our multimeters would even notice, we're unable to monitor every output in real-time simultaneously. To record idle voltages, I simply let the system sit idle in Windows for 20 minutes. For load voltages, I ran Prime 95 (one instance per core), Winamp, AIM, multiple FireFox windows and defragmented the hard drive, all while playing Just Cause on max graphics settings. This combination of programs put a nice load on the system.
Voltage results between the two power supplies were pretty even and all voltages across the board were well within spec, with only a small amount of fluctuation on the 12v rail. Seeing as both of these units perform equally well, it really comes down to which one you like better in terms of aesthetics - the X-Pro with its traditional silver brushed aluminum case and black sleeved cables, or the X-Finity which sports a black brushed aluminum case and a rather new approach to cables. I wasn't too thrilled with the looks of the X-Finity's cables but they would be very simple to tuck away inside of a case and would make your overall system appearance very clean looking. The cooling fans used in each power supply were very quiet; some of the quietest I have seen used in a power supply. One of the coolest features on these power supplies is AST. AST stands for After Spin Technology. AST allows for the PSU, case and CPU fan to keep spinning several minutes after the computer has been shut down. This helps to cool the system down much faster than it normally would.
As for the number of cables, it would have been nice to have two more PCI-E cables. I had to use adapters to power my 8800 GTX SLI system, which meant I had to use four Molex connectors. This left me with only four free Molex connectors. After making all of the necessary connections, I only had one spare Molex. The length of the cables was about average. If you have a full tower system, you may or may not run into length issues. I don't have a full tower so I wasn't able to determine this for sure. Both the X-Pro and the X-Finity power supplies have a MSRP of $199.99 but can be found as low as $180.00 at various online resellers.
