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Question

Crossfire between old and new GPU

Mar 8, 2016 10:03AM PST

So I have an old Radeon HD 4870 x2, and I was wondering if I was to get a Radeon R9 380X, would I be able to use crossfire between them?

Discussion is locked

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Answer
I've looked at this before.
Mar 8, 2016 10:09AM PST

It seems that it works best with 2 of the same and some write you can find your high end GPU dragged down by pairing with too low a model instead of gaining. I'd remove the 4870 for power reasons alone.

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Note about power.
Mar 8, 2016 2:34PM PST

Figure 350 Watts alone for the existing system, 200 for the new r9 so for safety margin figure a single rail 800 Watt PSU

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If power didn't matter.
Mar 9, 2016 9:35AM PST

If I used the 380, with the 4870 connected via crossfire, would I get any better performance, or would it just be pointless/slow me down?

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There are prior discussions on that.
Mar 9, 2016 10:17AM PST

It's hit and miss. You won't know till you try and the power requirements look pretty steep for a minor uptick in GPU processing. The R9 380 looks to play games on high or ultra on 1080 screens all on its own. I wouldn't bother with the older GPU. it would be pulled and sold as soon as I got my new card all tuned in.

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Answer
Yes....but
Mar 8, 2016 2:16PM PST

I suspect when you couple a gpu with 1GB of vram to a gpu with 4GB of vram your perf will drop
verses just using the gpu with 4GB.

Try it see what the results are.

I hope you've got a whopper psu to run this test.

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Actually...
Mar 9, 2016 9:30AM PST

It has 2GB of vram, but I'm mostly concerned about whether or not connecting the two would have any adverse affects even after removing the crossfire.

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Adverse effects
Mar 9, 2016 9:52AM PST

Doubtful.
As long as you have a psu able to handle the load test it both ways.