Dos SLI Dobble memory bandwitch?

[aleksanderdev]

Hi.
Im not 100% sure of this yet but i belive that 256 memory bandwith isnt enough to handel 4gb vram.
Lets say this is true.

Would running SLI dobbel the bandwith? So a sli setup would have 512 bus working on both of the 2 cards vram?

Since vram dosnt dobbel with SLI, and if the bandwith dos. Than it would eliminated the problem with bus not being powerful enough to handel 4gb.

Example being the GTX 690. It has shared 4gb Vram over the 2 cores if i understod correctly. (Why cannot this be done with SLI?)
And each core having 256 bus, but in the specs of the card it says it had 512. So bandwich dos dobbel with SLI?
Unless this is a goofy selling trick from nvidia.

 

[bystander]

A 690 has 4GB split, not shared, between the two GPU's on the card. Each GPU gets 2GB's of dedicated VRAM. Nothing changes with the bandwidth.

 

[aleksanderdev]

Ah so confused.
From nvidias site.
GTX 690 Memory Specs:
6.0Memory Speed (Gbps)
4096 MB (2048 MB per GPU) GDDR5Standard Memory Config
512-bit (256-bit per GPU)Memory Interface Width
Memory Bandwidth (GB/sec)384
So bandwidth and memory interface width are 2 different things.

Every singel online shop selling this cards, says it has 4gb, but if its 2gb per core, than its not true.
Than it is a 2gb card not 4.
Also says 512 bit but 384 Bus?
now 2x256 bit dosnt equal 512 in performance as its not shared.

 

[bystander]

It's marketing at its best. The have two of everything, so they add them together, because it exists on the card. However, each GPU works independently. One GPU renders 1 frame, the other GPU renders the next in AFR (alternate frame rendering), or in some cases, one GPU renders the top half of the screen, the other renders the bottom half.