Dark playback; Can view in MPC but not in MPUI

[#2]

I've just bought a 21" lcd and tried to play rmvb/ac3 mkv streams.
I updated my nvidia drivers for a 5200. But I'm getting 100% cpu and very jerky playback on an Athlon-XP 2000 with 3 GB of RAM. What's more in MPUI all streams I've tried play at near black.
MPC, if set to use Haali's renderer or VRM9 (renderless), will play proper brightness but still very jerky on anything more compressed than a VOB.
I've been through all the texture and resizing settings in MPC and Antialiasing and Antistropic filtering settings in the nvidia drivers. Nothing has worked.
I would really appriciate some wise words on this.
Thanks.

[pinkie_1]

in MPUI all streams I've tried play at near black
MPC, if set to use Haali's renderer or VRM9 (renderless), will play proper brightness
The info you provided converge into one conclusion : you have problems when using overlay.
BTW, which drivers are you currently using ?
For a (g)oldie 5200 card you don't need newer drivers. Please switch back to older detonators.
still very jerky on anything more compressed than a VOB
It seems rather odd that you're fine with MPEG-2 streams, but not with MPEG-4... Are you trying to play back 1080 content ?
Furthermore, be sure to disable any unnecessary things (in your case) like postprocessing, avisynth thru ffdshow etc.