Well, I never used to play games on my M3438G but now I do and notice the lag on every game I play (Trackmania Nations, Wolfenstein Enemy Territory, Hard Truck).
* In Wolfenstein Enemy Territory, it jerks and lags until you have been around the whole map and locations and "seen" all the characters, after which it must cache it in memory as it's relatively smooth after that (until something unforseen jumps out at you, like a new character or special effect), but it's a bugger while it's caching = I'm dead meat. I can't turn around fast enough while the computer lags as someone's shooting me (as it's caching their character or special effect as they're shooting me), so I'm dead before the glitching ends. Makes you mad.
* Hard-truck temporarily locks up for <2secs whenever it accesses and streams anything from the hard-disk, such as an audio snippet from the truck's "CB radio" or the like, so if you're carrying out a manouvre while it suddenly lags you will crash and require your truck to be fixed (needing lots of money), and you'll lose time on your truck run and your ratings. These take hours of gaming to make up for.
* In Trackmania Nations it brrrs and you lose completely control of the car. A bugger if you're absolutely sailing through the course in record time and you're completely wiped out due to it.
My HDs are indeed the Samsung, but they are in Raid #0 (striped) config, so I (hoped) that might even have been better (faster) than using them individually, but no the lag is there, proud as ever.
I don't fancy buying a 7200rpm HD as my computer already automatically switches off after several hours of intense gaming obviously due to overheating (I even have the laptop propped up an inch or two on all four corners, raising it off of the table to allow airflow underneath). The GPU is not overclocked either - default settings, and I elected to keep the fan on at all times. The fan and internals are as clean as a whistle.
System bios is 1.10c, graphics are v81.94 (as v91.33 blue-screen-of-death's on me - do I need a new BIOS version?), 5.41.02.39.60 is my GPU bios. Lappie is 2GHz (PM 760), and the RAM is 2x512mb DDR2 @ 533MHz.
The laptop's over the 12month warranty, so I guess it's my problem now. =/
I suffer from long term health problems and am house-bound, so it would've been nice to play games every now and then without problems. Will be several years until I will be able to get another computer.