A dev pointed something out that people are overlooking: A graphics card with a large amount of memory on it requires a computer system with a large amount of memory. Using a graphics card with a large amount of memory with a computer system with a small amount of memory (<= 2GB) will result in problems/performance issues.

I forgot to mention that . Thats why i have 8 gigs of memory running on a X64 windows 7 system .

Same here: 8GB system memory on Win7 64bit Ultimate with GTX590 (3GB memory)

He has X64 so 3gig switch is not needed .

I know it's not a super-card, but it runs all my games very well at high settings. SH5 is running at 1900x1200 with all the settings ticked at a lovely 50ish fps (with mods). The only thing I have to turn off is particles, which must be off, or the lag is unbearable. Still runs at 60fps stock, even with the lag. God knows what they did with the particle engine in this game!

I still get the occasional CTD, 2 today in fact coming out of Scapa Flow, but I'm trying to just tolerate it and keep my TC as low as possible. Thanks for all the tips guys, and for the excellent mods. Dynamic Environment is beautiful :)