Doesn't the battery life test in GFXBench normalize for framerate?
How do you mean? (granted I know a few things about GFXbench but it's not that I use it on a daily basis either). This is how I understand it so far: if you run the T-Rex onscreen test it'll give you 17+ fps for the T4Mi3. When it comes to the "Battery test - lifetime" it'll run again T-Rex onscreen for 30x times in a row and logs the lowest result achieved. The T4/Mi3 again achieves the same result as above which means that it doesn't throttle at least in that test; in another case where you have for instance T-Rex onscreen 20 fps and a "long term performance" score of 16 fps then the GPU is obviously throttling by up to 20% during that test.
On a sidenote I just tried something else to see how the sw reacts: plugged it in for the battery to charge and tried to run the battery test: it just stopped since it detected that it's charging
In any case one has to be careful with any of the displayed results too:
http://gfxbench.com/subtest_results_of_device.jsp?D=Xiaomi+MI+3W&id=559&benchmark=gfx30
Look at the two top results; I don't buy them to be honest. There must be a loophole somewhere in the benchmark which isn't all too surprising since it's not that easy to measure battery life either. As I said mostly an indication.
Since the S800 GPU is significantly faster than the T4 GPU in GFXBench 2.0, it's not much of a surprise that for a given framerate it would consume significantly less power. The S800 SoC also has the advantage of a more advanced and more power efficient 28nm HPM fab process.
Beyond doubt yes; SoC manufacturers don't have the same development/release cadence.
However the process in such a case just increases the efficiency a newer architecture has already. If I now jump on GK20A/K1 which is also manufactured under TSMC 28HPm I can see the following so far (always where I have fillrate results to get a better picture):
Lenovo K1, GPU frequency estimated at ~290MHz
~110 GFLOPs FP32 = 11.5 fps offscreen Manhattan
Adreno330@580MHz
~148 GFLOPs FP32 = 11.9 fps offscreen Manhattan
While of course there's no indication about power consumption yet for the first, the so far data indicates a better perf/GFLOP ratio for the first if you compare those two.
***edit: by the way NV is the first from what I can see with an OGL_ES 3.
1 driver, since no one seems to have noticed so far.