I searched all over online, and through these forums, but I still haven't found an answer, or even anyone with a similar problem.
I've got an Alienware x51 with
i7 3.4 ghz
6 gig RAM (1 gig devoted video)
Which runs Max Payne 3 at pretty much full specs at a solid 60 with no slowdown.
Last night, I take this rig over to my buddy's place to play a little, hook it up to his TV via HDMI, and my available video memory in the settings is around 500, less than half of what I am normally allotted. Needless to say, it ran like shit, and I had to turn everything down to the point that it looked worse than on a 360 and was barely playable with how choppy it was, pretty much negating the reason I brought it over in the first place. The resolution of the TV was higher than my monitor back home, yes, but I was still running it in 1680 like usual. We ended up just playing Driver San Fran, but even then, I had to drop the resolution down to around 1440 and turn off a lot of stuff, even then, very swimmy response time.
Back home now, I have all the video memory that I should and I have no idea what causes this kindof drop in performance, and what to do next time.
Thanks in advance if you have any ideas.