OCZ Silencer 750 Quad Crossfire edition review

PSU - Power Supply Units 108 Page 5 of 6 Published by

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Page 5 (Testing)

 

Load testing the PSU

In each PSU review we start like this: How do you test a PSU? In theory it's not that difficult, but in real-life situations it's very difficult with such a highly rated PSU. But the fact is that we do not have the gear in house to be able to stress this PSU to it's full capacity, we'll get darn close though.

We can connect everything we want, add more devices and overclock, but even then we'd peak at maybe ~550 Watts. But hey, let's try that out and see what happens.

So here's what we did. We took an eVGA Force 680i SLI mainboard (one of the most power consuming mainboard around) and equipped it with Conroe Core 2 quad Q6600 Processor, 2x GeForce 8800 GTX cards setup in SLI. After the installation we loaded the latest drivers, and enabled a seriously funky gaming experience and power hungry system. Pretty spiffy setup, don't you think ?

Now to stress power consumption little more we overclocked the 4 cores on the CPU towards 3.0 GHz, had the DDR2 memory running at a blazing 1147 MHz and the two GeForce 8800 GTX cards overclocked toward 625 MHz on the core and 2100 MHz for its memory.

OCZ PC Power & Cooling Silencer 750 Watt PSU

We now select a gaming experience at a monitor resolution of 1920x1200 (a good balance between hefty GPU usage whilst using the CPU at maximum as well). For this paeticular test we used X3: the reunion as it's proven to be a little more demanding than 3DMark (we learned the hard way). It's a total bitch on graphics cards; it makes the graphics cards sweat! At 1920x1200 we enable 8xAA and 16xAF to make sure the graphics cards were working hard! The balance of these settings also ensures me that that the CPU is utilized as much as can be, although not one title is really optimized for Quad core .. we did raise the bar.

Now at this point I realized that we're stressing the PSU slightly as it's didn't get even slightly warm. So we added fan's, some extra lighting coming from the chassis, and enabled water-cooling on the CPU draining it's power from the PSU.

Two things we monitored... We monitored peak PC power consumption with a wattage meter. And we tapped the voltage lines with a multimeter to see if we could detect any fluctuations.

Okay you get the idea already, stable as a rock and all that without any harsh noise from the fans. Pretty "enthusiastic" stuff. Let's place our findings in a chart. We pushed a maximum of 571 Watts with this new system.

Here we took (multimeter) some of the voltages in both IDLE and LOAD (fully utilized) modes. We noted down the lowest and highest value in both idle and the PC under load. If a PSU is unstable we'd see some fluctuation, differences and discrepancies which can result in system instability.

For gamers with SLI/Crossfire setups, the most power draw will be at the 12 volts rails. Above we can monitor the voltage distribution lines we monitored.

We have measured all voltage lines with a multi-meter directly at the device or mainboard. Again: these are not BIOS measurements. We measured two "states". The system pretty much doing nothing (idle) and the system stressed out 100% (load).

Now, what you need to understand is that on each of the voltage rails, a 5% tolerance would be the accepted as normal according to the ATX spec, meaning the power-supplies actual voltages should stay somewhere in-between the values. Clearly this is not an issue.

When we look at total PC system power consumption we need to realize we are pulling roughly 539 Watts on this system which ensures me that it's a really efficient PSU, last weeks tested SolyTech PSU pulled 571 Watts on the same configuration.

Excessive numbers yes, but the PSU didn't seem to push really hard. The PSU remains cool, the voltage rails stable.

This OCZ red devil is stable for sure, and remember this was tested on a very expensive 2500 USD NVIDIA High-end SLI and overclocked system.

OCZ PC Power & Cooling Silencer 750 Watt PSUSystem powered off - still consuming 11 Watt

OCZ PC Power & Cooling Silencer 750 Watt PSU
System powered on in idle (overclocked + SLI) - 302 Watt

OCZ PC Power & Cooling Silencer 750 Watt PSU
Maximum peak wattage measured between the wall socket and PSU.

Sound levels - we have to include a quick stroll regarding noise levels these days. I've had cheap PSU's in this office that likely could have functioned as active rotating helicopter blades when they got a little hot. This PSU doesn't need much wording in this regard though, it simply is quite silent, yet audible. The heat on the inside of the PC is being sucked outside the PC, creating airflow with the help of a 135mm fan for quiet cooling due to its ability to move a large volume of air at low RPM. Additionally we see a rear mounted 80mm fan for optimal airflow and thus cooling. So, hot air traveling in an upwards direction will be partly ventilated towards the outside where colder air is due to ventilation. Quite silent and sufficient enough to cool the PSU.

dBA levels are hard to measure, we did however, and the results: Reasonably silent at ~35 dBA which pretty much can be classified as inaudible to  normal noise levels.

OCZ PC Power & Cooling Silencer 750 Watt PSU

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