PSU Inside

The quality assurance passed sticker covers one screw. By breaking it you void your warranty.


The inside looks just like any other regular power supply, except that it doesn't take up that much space.

Performance

Since this unit is a video card power supply it has just 12V as output. The input voltage is a range from 100V to 240V which means the unit auto senses the voltage you have.

We tested the unit with two ATI Radeon X1900 XTX video cards and a cheap generic 300W power supply on an Athlon64 system.

Without the Power Express the 300W PSU was overloaded with a real power draw of over 400W, however it still kept the system running stable. But while it was running you could hear electrical noises coming from the PSU, also the fan was running very loud at its maximum speed, yet the PSU was very hot to the touch.
The 12V line was already quite low at idle with 11.87 V. But what is more scary is that during peak load it dropped down to 11.16 V which is clearly outside of the ATX specification (minimum 11.40V). The huge power draw number of 686W is because the PSU is running completely overloaded. Since it was never designed for this load the losses due to inefficiency are very high.

After the Thermaltake Power Express was installed, the 12V load of the video cards wasn't putting strain on the PSU anymore. As you can see in the graphs a major portion of the consumed power is handled by the Power Express now. With this setup the 12V line on the main PSU dropped to 11.63V, very acceptable for a PSU of this price-class.



Another important fact is that even with two X1900 XTX cards the load on the Power Express is only 181 W which means that there is still quite some juice left in the 250 W maximum output.

Even though the PSU gets warm during heavy use it does not really increase the case temperatures noticeably.

We also tried if we could overclock the CPU or video cards even further, but there was no change in maximum clocks, even though the supply voltage was a lot more stable.