Sigma SP-700 &00W ATX Power Supply Review

Here is a quick view of the top and sides of the unit. I am always a big fan of manufacturers that leave the sides clear of markings for a clean installed look. The finish is a nice glossy black that definitely looks better in person.

Here is a closer look at the Hexflo mesh back surface. The two vertical metal lines shown at left and just off center are two of the three heatsinks used to cool the system. These are quite small for a normal unit but with just 700 W to cool, they may be enough.

I installed the Sigma SP-700 into my AMD build using an ABIT Fatal1ty AN9 32X Motherboard based on the Force 590 SLI chipset. The build includes an AMD Athlon AM2 5600+, two 8800 GT cards in SLI and a 4 GB kit of Mushkin XP2-6400 modules. Storage was provided by both 160 GB and 250 GB Maxtor SATA II drives and a Lite-on 16x DVD burner all mounted in the NZXT Tempest case.

The SP-700's extra cable length had no trouble handling the inverted design of the NZXDT Tempest though I did have to run a couple of rails across the board. Here you can see how clean the install looks with no annoying stickers to mar the outside surface on my windowed install. Now we just need to add the Velcro cable ties and we are in business.

To test the SP-700 I ran the system overnight idle before capturing these numbers using the ABIT uGuru. With the test build featuring a single AM2 processor and a set of 8800 GT video cards, the build is representative of a large percentage of the gaming builds out there today. Using the Power distribution and overall Wattage as a guide, this also represents about the highest build I would comfortably be looking at a 700W power supply for as well. Although the rails exhibited some movement at idle, everything remained in spec.

Testing (Load):

Next I put the build under load by running Stress Prime 2004, better known as Orthos and Futuremark's 3DMark Vantage simultaneously in two back to back sessions before capturing the following:

load

As you can see the numbers look remarkably similar. I did again experience some little droops in power during testing when validating with my trusty multi-meter but over all the variance remained well within the spec.

BIOS

To further test the rails I fired up the system to the BIOS and rechecked the 12 Volt rails with my trusty Cen-Tech multi-tester. While the multi-meter is no oscilloscope; I noticed only very minor changes in voltage. I also kept the Multi-tester up during an hour session of Team Fortress 2 but never noticed any major variance.

Conclusion:

The Sigma SP-700 is definitely a more subdued design that the Sigma Shark model we last reviewed. With the SP-700 we have a no frills design that is clearly targeted at keeping things simple. During testing the SP-700 was quiet enough to not be heard over the two video cards as well. I was initially nervous about the size of both the unit and the heatsinks but during testing the exhaust never got overly hot.

The Sigma SP-700 is not the most stable power supply we have tested with some very minor movement in both the 12V rails and the 3.3V rails even while idle but the variance was never large or out of spec. This is not abnormal but stability and consistency of the rails is critical to any overclocking effort. With a price point in the $100 range, the Sigma SP-700 faces some tough competition from the big boys on the market. As the prices come down I would expect the 700W power supplies to become a bargain hunter's dream, keep that in mind when shopping for the SP-700.