The company has decided to keep Intel DDR3 memory as the system for future chip Intel Haswell. The reasons for this are primarily intended for the user and your pocket, because in this way they can have a very affordable price memory while definitely comes DDR4.
However this decision means that because of its potency GT3 iGPU has problems of bandwidth in graphic field. So during IDF the company has presented several aspects of architecture among which are to be 128 Mbytes of on-chip buffer.
In this way they ensure that the GPU loading basics work efficiently in this fast memory and textures into RAM and other borrowed catching system.
It is similar to a measure that took AMD years ago pre-APUs-with SidePort memory, but in that case were plated directly megabytes connected with the processor. So, let’s wait and watch that what will be the exact Intel Haswell processor performance and specs.