Question Crossfire - cards with different ram amounts.


Dec 8, 2002
I was playing around with two old 4850s last week, and I got them going in Crossfire. These cards were "retired" but I played with them. And if it is not common knowledge, HD 4000s are not supported by Windows 10, but if you roll back the driver to 1-13-15, both HD 3000s and HD 4000s work play older games fine.

Anyway, Crossfire worked, too. With the GPU inflated price situation, to gain some additional gaming power in my garage LAN Party lab, I set up two computers with 5850x2 Crossfire on computers that were used more frequently. With some lesser used computers, I started playing with GTX 260s in SLI and two HD 4850s, just so the extra ones would work OK. The 4850s use less power.

These are mostly going to be playing older games.

Anyway, one 4850 is 1G and one is 512 MB. Because the cards only use ram from one card in Crossfire, can the 1GB card be the primary so the Crossfire setup will be 1 GB?

The system is pulled apart now, but if it was 1 GB two 4850s might still have a function in my computer lab.

This is largely academic, but I am curious. I will get it going again this weekend and see for myself.


GPUs in SLI/CF use their own local VRAM. Assets get copied to both GPUs so they don't have to access each other's VRAM over the much slower PCIe bus and the amount of VRAM games can use is effectively limited by the weakest of the two.