WMC playback issues (primarily) after may win7 updates

[prsa01]

System - 3rd gen i7 mobile (laptop) 16 gig mem, 2 tb external usb3 recording drive, ssd system drive. 2 hdhomerun dual tuner. 1 native mp2, 1 mp4 real-time encoding. No obvious system errors in event log.

I've had some some video driver/codec seeming issues for some time during playback w/pixelization/stuttering/delays that seems to have gotten worse after May win7 updates. Have not 100% verified whether issue occurs during recording or during playback.

I have never REALLY understood the whole codec vs graphic driver interaction relationship. I know at some point it was recommended on mcebuddy to back-rev, fairly significantly, the intel graphics drivers in order to be sure the built-in intel graphics were used. I had success way back when using the recommended driver rev to get the conversions using the intel hd-graphics. With MANY system/software changes since, I have never been able to replicate that success again even when reinstalling that graphic driver version.

Currently have fairly up-to-date shark07 codecs installed. That did not seem to make any marked positive or negative change when first installed.

So, any info or good source for info on how to systematically trouble shoot graphics related issues would be appreciated. Also, if anyone knows what specific elements windows update may replace that could have this impact.

Thanks for any ideas and guidance!