I am a prospective buyer of two used HD 6950s and two used HD 6970s looking to Crossfire them in two systems, respectively.
Problem is the motherboard I have now only has one PCIe slot, so I can only test each card individually.
I am looking to upgrade my systems very soon once I've acquired the cards.
Is it safe to assume that if both cards seems to be in good working condition separately that, once Crossfired with working bridges and driver optimizations/profiles are set, they will work well together?
What sorts of problems could I run into that are hardware-related?
Thanks in advance for anyone who has any knowledge and experience related to this.
Like yourself I would assume that if the card(s) work independently then all would be well in a CF'd configuration.
I'm not sure what you are asking regarding the hardware-related problems. Ensure that you you don't have a bottleneck from the remaining components, and obviosuly make sure you purchase a CF/SLI capable board.
Yes, testing both card idividually will ensure that any problems you might encounter with Xfire will not be because of faulty cards, but because of something else. This is very valuable information.
As for hardware issues.. well, just make sure you have a QUALITY brand PSU (corsair, antec, OCZ, cougar, seasonic, pc power & cooling, ect.) of at least 750w, which will be enough for the xfire on the 6970's. You can probably get away with 700w, but if you don't have a good psu, then you will experience problems running both cards at once.
Also make sure that you have a good CPU that you can possibly overclock a bit. This will keep the CPU from bottlenecking the graphical horsepower that two cards in xfire will bring. Any modern quad core cpu running around 3.6ghz will be fine. This also means you might want to invest into a different CPU cooler if you are running with the stock one.
Thirdly, two cards in Xfire will generate ALOT of heat, especially if there isn't a space between the cards. Make sure that you have a very well ventilated case so that you don't go and overheat yourself. You can use something like MSI Afterburner to measure temps.
I run SLI 560ti's and I can tell you that the top card idles around 37C while the bottom one idles at 27C, and this is WITH a space in between the cards, so yeah.. might want to take that into consideration when buying a new MOBO.
I know it seems like alot to deal with, and even with all these things, more can go wrong with drivers and such, but if you can get it working, its definately worth it.
By hardware-related questions, I was theorizing that perhaps the components that establish the CF link aren't used while in single card mode, so if those are not in a good condition, it might affect my results when I try to CF.
Well.. Think about that for a second. What things affect Xfire? The Xfire bridge, but those are hard to mess up unless you are actually trying to destroy them.. The motherboard's PCI-E slots? Well.. you would be out of luck there and need to get a new mobo, but you won't know unless you try. Only other thing is the PSU that needs to be powerful enough to handle two cards.
Aside from that, really there is nothing else that would effect it.