I had the 8400GS for about 4 months on my first build, it was a good card for me, it overclocked soo well, i wish my 4670 could overclock like that card...
I mean i could raise the core clock 200mhz+ and the memory 200+ shader like 300+ and it helped it a lot in games, over the stock speeds i would get about 5-9 Extra FPS just by overclocking the card, this was important because i wanted my games to be ran at the highest possible settings, so it was important to maintain that 30FPS+ i think i could play @1024/1280 @ like 35fps, and i had it at low settings, this is for COD4.
So i would overclock the card first before you update, and see the results you get.