The dark satanic rumour mill has manufactured a yarn which suggests that Intel’s new Haswell architecture will have L4 cache which can be shared between the CPU and the GPU.
If it is true, then Haswell should provide some improved 3D performance.
The source of the rumour is VR-Zone, which claims to have spotted evidence that the Haswell launch line-up will include desktop chips featuring integrated graphics some two or three times faster than Ivy Bridge.
Part of this is thanks to a new layer of cache memory. In addition to the usual L1, L2 and L3 cache layers, VR-Zone claims Haswell is to ship with a chunk of L4 cache. L4 has only been seen in expensive chips aimed at the high-performance computing market.
Haswell’s L4 cache is there for graphics. It seems that Chipzilla and AMD are singing from the same dark satanic hymn sheet, believing that increased coherency between the graphics and central processing infrastructure on chips is the best way to go.
Intel does not appear to have the clear roadmap of AMD’s heterogeneous systems architecture (HSA), but it seems that it wants to do the same sort of thing.
If Chipzilla pulls it off, it could mean the death of low and mid-range dedicated graphics acceleration hardware. This has been talked about for a while, even with the introduction of Ivy Bridge.
But as far as servers are concerned, it means that it will be possible to run instructions on either the CPU or the GPU independent of where the data is stored. This could remove one if the biggest bottlenecks in general purpose GPU (GPGPU) programming which is moving data.
We will not really see until Haswell comes out. As you would expect, Intel is saying nothing about the rumours.