Article by: Joe Anderson (Hardware Reviewer)
Edited By: Nathan Glentworth (Owner / Head Editor)
Product was submitted by: Zalman
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PRODUCT INSTALLATION AND TESTING

All hooked up, the ZM-PCM1 module and bay adapter with the VGA module attached, is ready to install in the system. It's now a simple matter to insert the bay device in an available 5.25-inch bay, connect the adapter cables to the AUX 12V motherboard connector and video card, and attach the appropriate PSU cables to the breakout boxes. I noticed a small Philips screw on the back of the modules that would indicate some kind of adjustability. With no information on the functionality, I left it alone. In the case it goes!

The hardware set we'll use for the testing is listed below:
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MSI DKA790GX Platinum motherboard
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AMD Phenom 9950 BLACK EDITION Agena 2.6GHz (@ 3.0 GHz) 140W CPU OEM cooler
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Antec TruePower New 750W PSU
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Buffalo Firestix 2GB (2 x 1GB) RAM
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EVGA 8800 GTS 640MB graphics card OEM cooler
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Seagate Barracuda 7200.10 320 GB hard drive
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Samsung SH-S203N DVD writer
While installation is straightforward, the relatively short adapter cables may present some challenges when trying to tidy things up. This, of course, will depend on the mobo connector placement and video card used. Let's fire the machine up and see how these babies work.

With the power on and the machine at idle, here's what the devices displayed. Tapping the Mode button allows the user to toggle between volts, amps and watts. I was surprised to see the voltage reading a bit low, and this was confirmed by testing the rails with a high-precision voltmeter. The Zalman devices read the voltage almost 3% low; not much but considering that they likely calculate the other values using this number, it may be significant.

Loading the CPU (top) and video card (bottom) yield wattage numbers that appear reasonable, but there are a few things that need to be considered here. For example, measuring wattage is a bit tricky. Probably the easiest way to do this would be to use a shunt with very low resistance and high accuracy to measure the current draw with relative accuracy. I'm assuming that the IC Zalman uses for these devices mimics this design, but I have no definite knowledge of this. If done properly, this could yield very good accuracy. Given that the CPU in most modern motherboards takes virtually all of its +12V from the auxiliary PSU line, this is not the case with the graphics cards. Video cards get a certain amount of their required power from the motherboard PCIE slot, so the total power consumption won't be displayed by the Zalman power meter. Similarly, one would need two VGA meters to get some idea of the consumption of a card with two power connectors. Nevertheless, useful information can be obtained from these little gadgets and they look very nice on the front panel of a case.