Graphics in VTMR

Ok so i have a 6600 and i seem to get frame loss whenever it rains or i go down to the beach area. also i notice that speech can sometimes get cocked up, basically somone will start some dialogue then it will break and repeat the same part again.

Is this because of my ram possibly. here is spec of my mchine

Amd 3000+XP
768 MB RAM
6600GT 128mb GDDR3
ATA133 80gb HDD
page file 3gb (ish)
DFI LAN part NFIIb


i think that is all you would need to know, so do you think its ram, processor, or graphics card. if its the card please note i will be crying.
:)