Intel is constantly trying to improve its integrated graphics in its processors.
With Sandy Bridge processors, Intel introduced HD 3000 integrated graphics solution, which is just capable of playing Full HD videos and some casual games.
With Ivy Bridge processors, HD 4000 graphics solution was introduced by Intel, which is capable of playing videos up to 4K resolution.
Since AMD failed to create the expected performance from its Bulldozer architecture, Intel has an upper hand against AMD in terms of processor (CPU) performance. But AMD is far ahead of Intel considering integrated graphics performance.
So Intel is constantly headed up in improving their integrated graphics solution. In this situation, it is already known that upcoming Intel Haswell processors will have graphics solutions with better architecture and more number of (ES) Execution Units.
Prior rumours revealed that GT1 and GT2 are the model numbers of integrated graphics in Intel Haswell processors, but now a rumour says that GT3 is the model number of the integrated graphics in higher end Haswell processors and 15W Haswell processors that are to be employed in notebooks.
But remember GT3 is only for high end Haswell processors for Desktops, so lower end Core i3 may not get GT3 graphics solutions.
Pattern of these processors are already sent to manufacturers, to make their products compatible with this graphics solutions.