PC Reboots when video card set to a certain overclock - PSU?

[DarkenReaper57]

Hello everyone,

I have a Sapphire Toxic HD6950 2GB that I'm overclocking. The shaders were (fortunately) unlockable so I'm now overclocking the card and stress testing using Furmark.

I can play the Unigine Heaven benchmark with 920/1400 with +75mV vcore and Powertune set to +50% to make sure the GPU isn't power-limited. But when Furmark runs (and stresses the card even more), my PC reboots. I'm guessing this points to the PSU not supplying enough power on the 12V rails. Does this sound accurate?

My system is in my sig, and my admittedly older PSU is a:
SilverStone Zeus ST65ZF (ENS-0565) (650W) - Quad 12V rails
http://www.silverstonetek.com/product_legacy.php?area=usa&model=st65zf
http://www.silverstonetek.com/downloads/Manual/EN-ST65ZF-Manual.pdf

I'm using the two PCI-E connectors for the video card (rails 12V3 and 12V4). One has a 6-pin to 6+2 pin adapter. Maybe my PSU just isn't up to the task?

 

[chithanh]

If your CPU is overclocked, then maybe the additional power draw from the PCIe slot causes the problem. See if downclocking the CPU helps.

 

[sirmonkey1985]

that or the overclocks just not stable in furmark..

 

[enieves137]

Yes your going to have issues if your using old PSU to run new hardware. The peak and continuous power will change with new hardware and possible the PSU requirements don't work. I think your exceeding the PSU requirements.

http://en.wikipedia.org/wiki/ATX

•Amperage = Wattage / Voltage
•Wattage = Voltage * Amperage

For example: First look at what your video card draws, most cards will have a spec +12vdc and 22 amps = 264watts. SLI or Crossfire then double the wattage.

Stress test will increase power consumption, if your overclocking then your at max continuous power.

 

[manumitx]

Is there software that monitor and alerts when various hardware isn't getting the right amount or power? Best I can tell is everything I have has enough power, but it would be nice when the CPU and the GPU are pushed hard what my system is trying to draw and what its actually getting. I have an Asus motherboard and an Antec power supply.