Answer me if i can crossfire them, thanks.
Both chips are based on the same Pitcairn silicon. The R7 370 is Pitcairn Pro, while the 7850 is Pitcairn XT.
While technically you should be able to Crossfire them, you shouldn't expect significant performance gains by doing so. The slower of the two cards, the 7850, will likely drag that configuration down as it has lower clocks than the R7 370.
But it will be an improvement? I have the 7850 on my desktop getting dirty and i want to use it.
Depends on the game, some do not support Crossfire, others do fairly well.
Only in DX11 and lower applications. This running of the slowest card was fixed in DX12 and Vulkan, they both perform at max spec due to the ASync compute threading.
AMD CrossFire™ Compatibility Chart
While those charts show what configurations are officially supported by AMD, cards using the same silicon family may work, although are technically unsupported by AMD.
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