new monitor high res constant restarts, HELP

my PC

CtD E6300, AC7
2G DDR2 533,
Nmedia 500W 140mm fan PS. ultra stable (read reviews)
Asus P5B standard
sapphire X1950 pro
bout 17 fans, inc 2 dir under vid card.
nothing OC at the moment, hard to OC 6300 with 533 ram you know.

been running this system for about 4 months with no problems what so ever, games run beautifully, no restarts, most importantly Bf2. so just upgraded my monitor from a 17in to a 22in widescreen, of course making me change my native res from 1024-768 to 1680-1050, also had to change my resolution for BF2 to as high as BF2 can go, 1400-1200 or around those lines. ever since i started playing with this new monitor i am getting about 7-8 minutes of play time until i get Black Screen and a sound loop for a minute or so, then my PC has a hard crash, and about 50% of the time i get a beep-----beep-beep-beep, (award Vid card fault), simply re-inserting vid card and restarting fixes this. the system works perfectly outside of 3d apps no problems what so ever, but when i try to play BF2 boom. About 10% of the time ATI will reset my GFX without a restart and shrink bf2 to desktop but the instant i click bf2 after this i get the restart. i had my other monitor hooked up at the start for dual displays but it seemed to make it worse. note i recently wen't from 6.12 to 7.1 as well, but i played for a few days fine with this.