As always, this is just a rumor, and it comes from SemiAccurate, which by name alone isn't accurate all the time. But, Charlie has some interesting news, and according to his sources, "GT3 variants" of Haswell will sport an insane 64MB of memory sitting on the CPU package itself, right next to the processor die.
This memory will be enough to accommodate the frame buffer, which should help performance bottlenecks which are tied to the main memory interface. Earlier reports were talking about desktop variants of Intel's Haswell sporting a dual-channel DDR3 memory controller, and we all know that there's only so much bandwidth you can suck out of a dual-channel memory controller.
In an earlier report by Charlie, he said that Haswell's integrated GPU will have five times the shader performance of Sandy Bridge's IGP. If we take into consideration the 64MB of onboard memory, we should be in for some pretty big performance improvements, if this rumor turns out to be true, that is.