Haswell will be quite an impressive chip as it currently promises higher performance per clock, better battery life with notebooks and even significantly better graphics part, something that Intel has been lacking for quite some time.
According to the info, Intel plans to squeeze in L4 cache to boost memory bandwidth and lower latency for some of its Haswell SKUs at least. This variant of the Haswell is internally known as the Crystal Well and should feature much larger L4 cache part. The details regarding the L4-cache size are still not clear but might end up to be up to 64MB dedicated exclusively to graphics.

According to information, the L4-cache could be dedicated to the GPU while some other sources claim that L1-, L2-, L3- and L4-cache will be shared between the CPU and the GPU. The Crystal Well will be exclusive to high-end lineup and Core i7 CPUs. It is practically technology borrowed from consoles which used L4-cache in order to better deal with textures and antialiasing. It was considered by both Nvidia and AMD, ex. ATI, but it would be raising the transistor count too high.

The Crystal Well certainly sounds impressive and it will certainly bring a massive boost compared to Intel's previous iGPU solutions.

Source: Fudzilla.com