I tried ALL,
CoreAVC seems to work best. But cost me $12 !!
I was able to play full 1080p MKVs on my little c-50 netbook - FLAWLESS.
here is a turorial:http://imouto.my/watching-h264-videos-using-dxva-clearvideo-version/
All the others worked fine on my desktop, but that had plenty of GPU and CPU power.
So, for my my machines with tiny muscles and its itsy bitsy bits & peices, I had to find a solutution that can use all it's little high-tech parts: DXVA, GPGPU, UVD 3(AMD), etc.
I was still required to install Media Player Classic, DirectX 9 runtime 2010 (don't know why), Haali, LVA Secoder, etc. Basically it was a pain in the ass.
VERY surprised how immature codecs, drivers, players, etc are.
I expected to just install the newest driver, find some MKV codec, and play on normal Media payer - WRONG.
I hope I can get all this to work just by installing Windows 8,9 later with all the fancy hardware read through some abstraction later.