Last week, a rumor indicated that the next generation Intel CPU, aka Haswell, expected in about one year, will introduce a fourth level cache. SemiAccurate confirms the information and add interesting details. This new cache memory known as Crystalwell will not be a cache shared between the CPU and the GPU, but a large memory only dedicated to the integrated GPU. It could reach up to 64 MB and would allow the GU to work without sharing RAM with CPU cores. Based on claims, the bandwidth of this cache memory could speed up some processes up to 5 times, so ti could indeed boost performance of such integrated GPU, as long as it does not require more than 64 MB of memory it will not request central RAM.
It also confirms that Intel is working hard to boost performance levels of its integrated GPU to compete with third party solution based on discrete GPU. This is probably to offer a graphical chipset-based solution able to challenge NVidia and AMD discrete solutions for the ultrabook market.