How does Crossfire handle a failed secondary graphics card?

[Johnmcl7]

I have a pair of AMD 6950's and today out of the blue, the PC stopped booting - it initially powered straight off when I pressed the power button and then when I tried again it switched on and put all fans to full then did nothing else, no output on the monitor and no beep to indicate it had made it to POST. I took out the second 6950 and still the same, removed both cards and the PC made it further and put the fans to normal then beeped to indicate the lack of graphics card. I put the secondary card into the primary slot and the PC fired up fine the put the original primary card into the secondary slot (both cards installed but swapped over from their initial position) and the PC booted fine. I expected when I fired a game up that had Crossfire support it would go horribly wrong when it tried to use the second card but it appears to be working ok.

The obvious solution to test the card is to swap them back again and see if the PC fails to boot but I'm loathe to this when it's working fine at the moment. I'm wondering if there's any other testing I can do, I've run GPU-Z and it's showing both cards and giving back readings for temperatures and fan speeds. What gave me concern is that Titanfall was freezing very briefly regularly although I've not played it in a while so that may be down to something else. I tried the 3Dmarkvantage benchmark but it seemed to be running a constant framerate for the first run, for some reason the monitor switched to power saving after the first benchmark. I also tried Tessmark which completed fine although was the same with and without Crossfire disabled.

Are there any other ways to test to see if the second graphics card is working properly? I've read some recommendations for MSI's Afterburner software to show the data from both cards during a game so I was planning to have a look into that further.

Thanks,
John

 

[KingFatty]

Could you have a bad power connection?

Maybe your initial problem was because one of the PCI-e power connectors fell out on one of the cards, but messing around you now fully seated all connectors so it's good as new?

 

[Johnmcl7]

I don't think so as both power connectors were still firmly plugged and it's difficult for them to come loose as there's a plastic cover across the top of the graphics cards which clips into place and protects the cards. The cards were still secured at the output end (they have screws rather than clip in mounting mechanism which I find aren't always that good) and on the other side the cards slide into slots to hold them in. It's looking like I'll need to get them out and see if the second card is still screwing the boot cycle.

John

 

[psolord]

I'd suggest to also check system behavior with each stick of ram alone.

I've seen some weird stuff from bad memory, which surprisingly memtestx86 was reporting to be fine, but wasn't!

 

[Johnmcl7]

It's looking increasingly like it's the second graphics card, I tried Titanfall again tonight with Crossfire disabled and it ran without issue.

John