My initial i7 game test doesn't look good for those hoping for a miracle. Letting X-Plane 10 fly around while watching HWiNFO64 on the second screen as I type this on my laptop... GPU tops at 598mhz, and unfortunately drops to 400-450mhz occasionally. Temps stabilized around 70C for the CPU and 80C for the GPU. CPU is throttled to 1400-1700mhz.
Oddly, while painfully slow, it's a stable framerate, hovering around 20fps. By comparison, this same test on the i5 results in GPU clock speeds of 598mhz-900mhz with 25-28fps with game stuttering drops to ~15fps as the GPU clock fluctuated.
By comparison and still a sore subject with me, the SP2 ran a stable and enjoyable 28-30fps all day long during this same test.
I will say, I think the i7 is the overall better option than the i5 for gaming at this early point in my testing (but not by much!), for the simple reason that the throttled HD5000 GPU at 598mhz (where it seems to have stabilized, just like the i5 HD4400 does) provides a more consistent experience due to having twice the EU units.
But, the SP2 is still unfortunately the better option if gaming is an important goal in a Surface tablet. While watching the loads/temps/clocks, I just don't see Microsoft having much headroom to let the GPU run any faster in further firmware updates on the SP3. Even at 598mhz with the CPU throttled back to 1500mhz, the GPU is still at 79-82C. Fans blasting of course
For basic office work it is of course fine, but then so is the i3.