I recently completed my first build. Everything has been running well, except my computer doesn't seem to recognize my video card, and defaults to my i5 2500k's graphics core, even though the card seems to be on (fan spins).
I've tried everything I can think of (re-mount graphics card, set bios to favor pci-e graphics, install new chipset drivers, make sure to plug in both 6-pin connectors) but I can't get my computer to recognize my graphics card's presence.
The video card is an XFX 6950 1GB. Motherboard is an ASRock pro3 Z68.
Because the fan on the video card is spinning, I don't think its a power supply problem (I have a 500w OCZ modxstream, which meets minimum specs) so now I'm trying to decide if the pci-e slot on my mobo is gone, or if the card itself is just bad. I don't have an extra video card to test my system with, unfortunately. Any ideas?
Managed to get a friend to try the card in his system. To my surprise, it worked. (max-settings bfbc2... so beautiful!)
This means it is either a power supply or motherboard problem. My power supply is unfortunately a dual rail config, so this means it can provide 75 watts from the first rail for the pci-e connection, combined with 216 maximum wattage from the second rail for a total of 291 watts to the video card and peripheral devices... should this be enough?
Barrings a PSU problem, I think i'll have to RMA my mobo. *cries*
What is the make and model of your friend's power supply unit?
The Radeon HD 6950 has a Maximum Board Power of 240 Watts but its PowerTune Maximum is set at 200 Watts. If the card hasn't been modded to a 6970 and the PowerTune Maximum is left at 200 Watts then the graphics card itself may draw up to 16.7 Amps from the +12 Volt rails.
Since the graphics card has two 6-pin PCI-E supplementary power connectors that means it can obtain at most 150 Watts (12.5 Amps) through those two power connectors (from +12V2 on the PSU) assuming it adheres to the PCI-E power specifications. The remainder would be obtained through the PCI Express x16 slot (+12V1 on the PSU).
I've read TechPowerUp's AMD Radeon HD 6950 1 GB review where they mentioned that the card's two 6-pin PCI-Express power connectors are specified for up to 225 W power delivery. If the card indeed draws all of its power through the two 6-pin PCI-Express power connectors it would not meet the PCI Express specifications. This would mean that the graphics card would draw up to 16.7 Amps from +12V2 leaving only 1.3 Amps for your SATA hard disk drives, DVD drive, CPU & case cooling fans, etc. which isn't sufficient.
Try a better power supply unit first before you start replacing the motherboard. Borrow one if you have to. If you find out that the power supply unit is insufficient get a better name brand one. It should be cheaper and less hassle to replace than a motherboard.