- Aug 26, 2013
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- 10,510
I've inherited a PC at work, but I can't get the included graphics card recognized by Windows 7 and it doesn't produce any output. Even though a collegue stated the setup worked before, I think the PSU is underpowered.
CPU: AMD Athlon II 935
Mobo: Gigabyte GA-MA785GMT-UD2H
GPU: AMD HD 6990
PSU: OCZ 500W (two 12V rails)
I tried the card in my home PC (650W PSU). On bootup (before driver installation), the fan spun to max rpms twice (I'm guessing once for each GPU on the card). It produced output and was recognized in Windows (drivers automatically downloaded). So the card works.
In the work PC, the fan spins, but doesn't spin up to max rpms during boot. Since the fan also spins without the PCI-E power plugged in, I'm guessing it's not receiving enough power. The PSU has one 8-pin PCI-E power cable and there is a 2-molex to 6-pin PCI-E power cable plugged into the other 8-pin power connector. The BIOS is set to use any PEG (PCI-E) graphics first, then the integrated graphics.
I'm going to try putting another graphics card in the work PC to ensure the PCI-E slot works. If it does, am I correct in assuming the PSU is underpowered and I should buy a 600W, single-rail replacement?
Thanks.
Update: I tried with a HD2600 and it works fine, so I think the card is underpowered. I'll use the onboard video now and keep an eye out for a good quality 650W (or so) PSU on sale.
CPU: AMD Athlon II 935
Mobo: Gigabyte GA-MA785GMT-UD2H
GPU: AMD HD 6990
PSU: OCZ 500W (two 12V rails)
I tried the card in my home PC (650W PSU). On bootup (before driver installation), the fan spun to max rpms twice (I'm guessing once for each GPU on the card). It produced output and was recognized in Windows (drivers automatically downloaded). So the card works.
In the work PC, the fan spins, but doesn't spin up to max rpms during boot. Since the fan also spins without the PCI-E power plugged in, I'm guessing it's not receiving enough power. The PSU has one 8-pin PCI-E power cable and there is a 2-molex to 6-pin PCI-E power cable plugged into the other 8-pin power connector. The BIOS is set to use any PEG (PCI-E) graphics first, then the integrated graphics.
I'm going to try putting another graphics card in the work PC to ensure the PCI-E slot works. If it does, am I correct in assuming the PSU is underpowered and I should buy a 600W, single-rail replacement?
Thanks.
Update: I tried with a HD2600 and it works fine, so I think the card is underpowered. I'll use the onboard video now and keep an eye out for a good quality 650W (or so) PSU on sale.
you have more than enough to crossfire. The chart I used earlier actually was the total wattage it drew for the system adding up to 400 watts on load with full rig, adding another 150 gives up to 550 total, but it's bad to have your PSU working hard all the time since it reduces it's life span. The AX is a tier one PSU so you are perfect 
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