Not sure if this is a coincidence or if I'm imagining it, but after I did the Xbox 360 update a few days ago (250GB S model) I seem to be seeing an ever-so-slight performance hit - i.e. frame rate ever so slightly slower. I first noticed it on the main dashboard menu, scrolling left and right didn't seem to be as silky smooth as it was, but then I watched a 720p mp4 file from my USB drive (which i do all the time) and a couple of times throughout the video it stuttered, which I've not seen it do before. THEN, I noticed (and this may be a small thing because I couldn't say either way whether it did it before or not), the scrolling text banner on Pure judders a bit every 2 seconds.
It's probably not something most people would notice, and it's certainly not a game breaker by any stretch of the imagination, but is anyone else experiencing this or am I a special case?