Intel HD 4000 has replaced the HD 3000 integrated GPU in the Ivy Bridge processors. These processors are manufactured with smaller manufacturing process (22nm) and produce much less heat than the previous generation processors.
The test was done on our new notebook that came with the Ivy Bridge i7 3820QM processor and 16GB RAM. We are mentioning the CPU here because the performance of the GPU is highly depended on the CPU. The reason is that the GPU clock is set at different speeds in different CPUs. For example: In Core i7 3610QM processor, the CPU and GPU speeds are 2.3GHz (3.3GHz in Turbo mode) and 650MHz (1100MHz in Turbo mode). On the other hand, the speed of CPU and GPU are 2.9GHz (3.8GHz) and 650MHz (1300MHz) respectively.
Intel HD 3000 vs HD 4000: The 4000 GPU now has bigger cache which is shared with the L3 cache. Dual core processors have 3-4MB cache, while the quad core ones have 6-8MB cache memories.
With the HD 4000, Intel has clearly improved over HD 3000 by a long shot. However, you must keep in mind that performance of the CPU, in this case, is directly promotional to the performance of the GPU. So, strong CPU (such as i7 3820QM or i7 3610QM) will give you amazing GPU performance too. In fact, with such strong CPU and integrated GPU, there is no point in getting an Ivy Bridge notebook with a discrete low-end GPU.