I think your missing the point. There are many benchmarks that indicate the APU's are very sensitive to memory bandwidth, double framerates in some cases. The reason a frame is dropped or becomes a runt is that the second GPU, in this case a more powerful discrete GPU, has a frame ready before the first one's done. If the APU is better able to keep up it may push out more complete frames. Since it wasn't tested we don't know if this is the case, however we can't dismiss it out of hand. Higher end graphics also suffer from runt frames but they are pushed much harder than this configuration. More importantly 7900s run equal GPUs and equal Memory. They aren't as unbalanced as APU + GPU (or DDR3 + GDDR5), we just want to try and even out the playing field a little.
Here's a case were we would like additional testing to disprove said hypothesis, like you said science not magic or guessing. Science and engineering involve testing, refining, and careful thought, clearly you don't understand the basic premise of either.
Hello random person on the internet! Thanks for the mild personal attack.
Anyway. So let's start with the careful thought.
See, i did think of that scenario in which more bandwidth = more frames = the APU being able to keep up. However, I'll point to these four pages from three different articles (testing):
And specifically these three charts from page 5 of the memory bandwidth scaling article:
So what conclusions can we draw from this?
1) Memory bandwidth can unlock a lot more performance (22%) and push frames faster, and from the Richland review it would appear that the 6800K was achieving lower latency on its own and in dual graphics mode, especially with respect to this article.
2) However, as we note here, there's a difference b/w anti-aliasing modes, that should put some additional pressure on VRAM and the GPU, perhaps causing the dual graphics config to fall apart.Here simply "MOAR SPEEDY RAM" wouldn't have helped much. I'll come back to this in a bit.
3) Also note the results in this article, where Skyrim appeared to show low latency as calculated by FRAPS recorded frame times, however on screen there was a lot of stutter.
4) Look at the BF3 charts. Frame times remain similar and equally stuttery throughout, with some apparent improvement going above DDR3-1600. However, as you turn up the resolution, the frequency and magnitude of the stuttering becomes more alike b/w different memory configs. Also, the performance gain is maximum at 720p and minimum at 1080p, suggesting that memory bandwidth can't alleviate issues caused by an anemic GPU. Similar arguments have been made against the Xbone.
5) You talk of careful thought, so tell me this, if a balanced GPU setup with almost identical memory bandwidth (as identical as physically and statistically possible) still needs software side frame pacing/metering/buffering to make things smooth, do you really expect me to believe that an increase in memory transfer rate by maybe 20% at the most can alleviate problems that are partially caused by a far greater difference? In architecture, too.
I can sort of agree with InvalidError's remarks about a software fix on a similar problem helping out somewhere else (though in this case it would have been extremely improbably), but definitely not this "MOAR RAMS FASTER" train of logic.
6) So here's a more refined version of your train of thought, that i began with, before making that post. You can look at the other charts and draw further conclusions and refine your conclusions. I may be very wrong about it, and heck, i'll learn something if i am, but i don't see it happening.
Hope this helped.