My objective: I need a laptop that will allow me to play Starcraft 2 on High settings at the very least. I would also like this computer to carry me over into BattleField 3 (playable settings, hopefully at least medium) until I can work on customizing a gaming desktop.
HP Pavillion dv7t Quad
2nd gen i7 @ 2ghz
1GB Radeon 6770M
750 GB 5400 RPM HD
Dell XPS 15
2nd gen i5
The HP sports a 17' screen with offers a better resolution at 1600x900 whereas the Dell only offers 1366x768.
the 6770M is the better mobile GPU but also drives the tougher resolution. FPS wise the two laptops will probably be in the same ballpark so the question is do you want the 1600x900 resolution or the lesser 1366x768.
I don't think either of those will offer you high settings for bf3 but probably for SC2, but not because of the processors. it'd be the graphics cards that are the culprit. If i'm not mistaken, the 6770m is essentially the 5770, but being a mobile you'd knock it down one notch, so that'd make it a 5750. a 5750 is good at 1600x900, but probably won't be for much longer.
Perhaps the dell may be better in terms of frame rates, but only because the resolution is lower thus requires less horsepower.
I don't see the 540m, but since it's less than the 550Ti and it's a mobile, you're probably getting a videocard that's very similar to the 6770m with the HP lappy.
If i were to guess, I'd say that the dell would get slightly better framerates, but only because of the lower resolution. If they're the same price then go with the HP. with either choice you're being limited by the graphics card and the CPU can put out enough power.