7970/280x way to make 280x primary card in SLI?

Hardware Hub GPU
1

I have older hardware and see litte reason to update it atm but I have one annoying problem.

I have a 7970 and a 280x in my system the problem is the 280x clocks quite a bit better but by default the 7970 is used as the primary, in real world use cases for me my 280x rarely sees more than a 4% load and even that is uncommon. My system would most likely be faster if I removed the 7970 entirely or switched to single card mode and used the 280x. Is there some way I can make my system use the 280x as my primary video card wile crossfired?

2

No.

Especially because some games actually run worse with crossfire/sli.

3

hmm well I'll take your word for it. I do have use cases where both of them being in there is beneficial and graphics performance being a bit slower dose not effect me much so I'm just gonna leave it as is

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It would be really neat if you could have each card take as much load as it could handle proportionally. Unfortunately the way crossfire/sli works, requires both cards to be at the same "level".

BTW isnt the 7970 faster than the 280x by a small margin?

5

No the 280x is the newer refresh of the 7970, both gpu and memory can clock higher. I got them for almost nothing after one of the times bitcoin was in the news and everybody failed to mine.

Its unfortunate I'm suck with the 7970 being the main card but such is life. Most of the time the 280x dose not even wake up.

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primary card does not matter unless if you play a game without crossfire, in which case, the top most card will be used.

3 Likes
8

No it won't it will always use the 7970 for most tasks. You can't even use the 280x for anything in single mode unless it's in software that specific ly designed to be able to use it outherwise it will just be disabled. AMDs driver's is designed this way when you mix these two generations of cards the older generation is basically the master

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That doesn't make any sense... have you tried manually disabling crossfire and doing it that way?

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Yes these is no way to use the 280x by itself without removing the 7970. If you disable crossfire the 280x is disabled and there is no way to switch over too it that I know of. You can use it with programs that use gpu power for non graphical things but thats it.

ruing the two generation cards together comes with some querks. The reason for this post was too see if anybody knew how to get around those.

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Maybe if you uninstall the 7970, reinstall drivers with only the 280X, then reinstall the 7970 afterwards it'll start using the 280X as a primary?

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I ain't gonna lie. The clickbait title triggered me.

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hmm.... waa?

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Yea, what he said. Uninstall all GPU drivers, remove the 7970, make the 280x the top card then install its driver. Then add the 7970.

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280x in SLI. You got me there.

Also from what I know If you have 2 different GPUs in crossfire. The crossfire will run on the lower vram. Vram doesn't stack.

1 Like
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Yeah that was totally on purpose too, I thought it might make a few people end up with a turd crossways

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So basically if you have a GPU with a 6gb vram and another with 8gb. Both will run at 6gb.

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Anyways when you have of both of these cards installed the drivers are designed so the 7970 is always first and also any 280x specific features are disabled. I knew that b4 I even bought them. I think I recall he who shall not be named syndicate did a video about it. This is what AMD intended, if there is a way around it its a hack of some kind.

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Both the 280x and 2970 have 3gb of v-ram and yeah if one card did have more you would still just be able to access the amount the lesser card had.

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Well sorry mate. Haven't had that kind of issue before. The closest issue that I had and I can think of was before when I installed my GPU drivers automatically, It will always gave me the drivers for 7970 and not the R9 280 drivers. So I had to uninstall the 7970 drivers and install the r9 280 drivers manually.

I have 2 R9 280 in crossfire.

21

the obvious solution is flash the bios but thats risky