Just updated OS, some videos are lagging sporadically
 

I've just upgraded from XP to 7 Ultimate 64 bit, I'm using the latest CCCP and the included MPC-HC to watch things, I've been noticing small instances of video slowdown and I'm unsure what may be causing it, I had no problems on XP.

I'm using a 2.67 ghz Quad Core i5, 4 gigs of Ram, and a Radeon 5770 1gig outputting through HDMI.

I'm not 100% sure, but if I close MPC-HC each time I load a new episode, it seems to help... though I might just be imagining it.

I know 7 most likely requires more resources than XP, but surely 4 gigs is sufficient for playing a video (with no other background programs running).

I'm open to suggestions, it's starting to get a tad annoying.

Give SMPlayer a try.

That is odd, I went from xp x64 to 8.1 and the frame skipping disappeared. Maybe the problem is about ram, since my computer has 8 gbytes or ram and 4 of vram. BTW, I use avast free antivirus, some antivirus eat up cpu cycles without you noticing, maybe you changed to another antivirus (or installed one) when upgrading?

I would probably look at the renderer settings. Outside of the codec, that is the other thing that can affect frame rates.