Z77X-UP7 Motherboard does not detect 2 of 4 Gigabyte 7970 HD GPU's

[Klaatu06]

I have an issue with a new build. Two of the GPU's are not detected by the device manager, and I suspect not POST'ing. If anyone knows how to display GPU Posting in the Bios or elsehwere, I'd love to know. Either way, I have four GPU's on this motherboard and only two are functional, and they aren't the first two orange slots, as the AMD catalyst control center detects multiple GPU's, but cannot crossfire even with the cables in.

My configuration has adequate power, tested good by a thermaltake ATX power tester and is as follows:

Mobo: Gigabyte Z77X-UP7 Bios version F5
CPU 3770K Intel (stock speed)
GPU's Four Gigabyte HG 7970 GE (stock speeds)
PSU EVGA Classified Supernova 1500W PSU
Storage: Samsung 840 Pro 256 Gb
RAM: Team 8gb (2x4Gb)
Monitor: Asus PA248

Everything is seated correctly and powers on in the case (lights blink fans whir) but I cannot figure out why the other GPU's are not operating. Is there a software configuration I am missing? A BIOS setting for PCIe configuration?

The advertisement is for 4-way CF/SLI, but there's nothing in the manual that's any help.

[wazza300]

Re: Z77X-UP7 Motherboard does not detect 2 of 4 Gigabyte 7970 HD GPU's

can you try with latest f6c beta bios

Z77XUP7.6c.zip

you can always flash back to previous bios if it doesn't fix things

[Vinster]

Re: Z77X-UP7 Motherboard does not detect 2 of 4 Gigabyte 7970 HD GPU's

and if you swap the two non-working GPU's with the two working units what happens? that would isolate the GPU's and the MB.

and don't rule out the PSU if it's new... I've had a few not work right out of the box.

Vin