Your AMD color issue sounds like a feature, not a defect. Look into full range (0-255) color vs limited range (16-235) and maybe you'll get the jist. For reference, Intel does not let you select the color range (heck even Nvidia doesn't) but AMD does.
Your comment regarding high power consumption is very strange considering the E-350 was low-powered enough to be put into netbooks (I have an HP DM1 with it) while the Pentium G620 is only a desktop part. Are you sure you don't mean temperature?
Also I am unsure what you mean by a poor DXVA implementation...I've been able to play 1920x1080 30fps or 1280x720 50fps AVC videos perfectly fine with low enough CPU utilization that I can even unplug the only fan in my DM1 and it will stay cool enough to never hit or go above 90c (that's Brazos's "danger zone", it does a thermal shut-off around 95c).
Anyway, recagarding the profile 2c, there is no "2GHz recommendation", there is only a recommendation that if you have an Athlon II x3 that it should be at least 2.7GHz. For reference, an Athlon II is like half as slow per-GHz compared to your Haswell i3. It's not on this chart, but Haswell is anywhere from 10% to 40% faster per GHz than Sandy Bridge:
http://www.tomshardware.com/reviews/processor-architecture-benchmark,2974-15.html wrote:
EDIT: After selecting the 2c profile, make sure you try it with GPU acceleration enabled in SVP as well as GPU acceleration disabled in SVP. Interestingly enough, regardless of whether you're using GPU acceleration or not, the 2c profile does in fact use different (lower) settings than the 2g profile.