According to a report published by Fuzdilla, the "Crystal Well" variant of Intel's Haswell range of processors will feature a massive 64 MB cache dedicated for graphics. Though the presence of L4 caches on graphics cards is nothing new, it has yet to make an appearance on CPUs since it would produce a "huge chip" due to the high transistor count of GPU cache memory.
While Intel certainly has the ability to fabricate processors with die sizes large enough to accommodate a large L4 cache, the size of this cache merits a degree of skepticism. Fuzdilla has also received reports that suggest that L1, L2, L3 and L4 memory will instead be "shared between the CPU and GPU."
From what we know, Crystal Well technology has been reserved for Intel's high-end GTS-based processors, so it is likely to only make an appearance on the most expensive Core i7 models. Regardless of whether these reports are true, we can safely expect a large improvement in Intel's onboard graphics when Haswell is launched later this year.