alt Hacker NewsSo can VRAM actually be used like regular RAM? E.g. if I have a 16GB module and my GPU has 16GB VRAM, could it be made so that my system reports 32GB RAM? What would be the implications of that?
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Tuna-Fish • today at 7:47 AM
Typical desktop GPU ram does not support being write-back cached by the CPU. With PCIe resizable BAR, you could map the area into ram, so you could technically fit 32GB to memory, but it would have to be uncached (or write-combine cached), which would make it really, really slow.
There are a bunch of datacenter GPUs that support full cache coherency, but if you used them like that the VRAM would be very high latency from the CPU. So it would only be really slow.
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It behaves like slower ram I assume, due to the increased distance from the CPU and overhead. Still, it’s much faster than normal SWAP which uses a disk or SSD.
How it is reported? As SWAP space, not as RAM.