Random VRAM idea...

[Supersonic Muffin]

So with games beginning to need more VRAM - technically speaking, would it not be possible for Nvidia and AMD to produce some sort of expansion card that fits into a PCI-E slot and maybe uses something similar to a SLI bridge to transfer data to your cards? this could help people who only have a 2gb card or cards and have the gpu power - just not the VRAM to use it all?

 

Think about it - by rights this should be perfectly possible - right?  so a pci card that connects to your cards with some type of high speed bridge and gives you another pool of VRAM to eat into?

 

Whats anyone thoughts here?

[TheRetiredSlave]

One word: Latency.

 

More than one word: While you could theoretically do that and it would theoretically increase the VRAM available to the GPU, you'd lose performance because the GPU probably wouldn't be able to access it fast enough (I mean, we're talking about nanoseconds here) to perform real work on data stored in the secondary VRAM pool.

[Supersonic Muffin]

One word: Latency.

yeah -but it is mostly fine over sli where data is transferred between cards right? and also mabye the cards existing VRAM could be a buffer that is used and the expansion card could somehow feed into that so its there when needed? 

[TheRetiredSlave]

yeah -but it is mostly fine over sli where data is transferred between cards right? and also mabye the cards existing VRAM could be a buffer that is used and the expansion card could somehow feed into that so its there when needed? 

 

AFAIK, not really all that much data does get transferred between the two cards. Both GPUs cache all the data that they need in their own VRAM (which is why VRAM doesn't "stack" in SLI/CF configs).

[Glenwing]

7GHz 256-bit GDDR5 memory bus: 224GB/s data throughput

Full PCIe 3.0 x16 if the entire thing could be used for only memory transfers: 16GB/s

Long story short, no, not really practical or feasible.

[-rascal-]

AMD is already using a new VRAM technology on the R-300 series -- HBM VRAM.