Most of this shouldnt come as a surprise. In a thermally constrained environment (17W for the entire package), its going to be difficult to get higher performance from a chip. If you start from square one trying to build a chip for a low power environment (e.g. for a tablet or smartphone) and scale up, you can usually get better efficiency than if you start out with a higher power part and scale downthe typical range of scaling is around an order of magnitudebut if you need more performance you might fall short. The reverse also holds: starting at the top and scaling down on power and performance, you might eventually come up short if you need to use less power.
As far as Ivy Bridge goes, HD 4000 can offer relatively competitive performance, but it looks like it needs 10-15W just for the iGPU to get there. On a 45W TDP part, thats no problem, but with ULV it looks like Ivy Bridge ends up in an area where it cant quite deliver maximum CPU and iGPU performance at the same time. This generally means iGPU clocks will be closer to 1000MHz than 1150MHz, but it also means that the CPU portion of the chip will be closer to the rated clock speed rather than the maximum Turbo Boost speed. One final item to keep in mind is just how much performance were getting out of a chip that uses a maximum of 17W. ULV IVB isnt going to offer gaming performance comparable to an entry level graphics solution, but then even the low-end discrete mobile GPUs often use 25W or more. Cut the wattage in half, and as youd expect the performance suffers.
So how much faster can we get with ULV chips, particularly with regards to gaming? Intel has a new GPU architecture with Ivy Bridge that represents a significant update from the HD 3000 iGPU, but theyre still trailing AMD and NVIDIA in the graphics market. Their next architecture, Haswell, looks to put even more emphasis on the iGPU, so at least on higher TDP chips we could very well see as much as triple the performance of HD 4000 (if rumors are to be believed). How will that fit into ULV? Even if ULV Haswell graphics are only half as fast as full voltage chips, they should still be a decent step up from the current full voltage HD 4000 performance, which seems pretty good. Too bad well have to wait another year or so to see it!