In short single card run down
.Multiple monitors (3) - 1. AMD 6970 2GB 2. AMD 6950 2GB.AMD can run three monitors with single card.Multiple monitors (2) - 1. GTX 570 2.5GB 2. AMD 6970 2GB 3. AMD 6950 2GB.All can run two monitors and more VRAM is better across multiple monitors.Single monitor - 1. GTX 570 or AMD 6970 2. AMD 6950 or GTX 560Ti.Here more VRAM isn't going to effect performance at 1920x1200 and only by a few FPS between 2560x1600 single monitor.In short dual card run down.Multiple monitors (2 or 3) - 1. GTX 570 2.5GB 2. AMD 6970 2GB 3. AMD 6950 2GB or GTX 560Ti 2GB.Again more VRAM is better across multiple monitors.Single monitor - 1. GTX 570 2.5GB or AMD 6970 2GB 2. AMD 6950 2GB or GTX 560Ti 2GB.Again more VRAM here isn't going to effect performance at 1920x1200 and only by a few FPS between 2560x1600.
Quick note on the AMD 6950 2GB unlock. By far this is the best price/performance
gain but not raw performance
. Even a heavily over clocked GTX 560Ti 2GB would be a great price/performance choice. HOWEVER, not all AMD 6950's are unlocking anymore. Sapphire Toxic AMD 6950
IMO would be best in this option to unlock with BIOS switch.
Keep in mind two things....If you looking for AMD 6970/GTX 570 performance then please buy one as oppose to take a risk. Secondly, an over clocked AMD 6970 or GTX 570 will beat in raw performance
an unlocked AMD 6950 with OC or even heavily over clocked GTX 560Ti.
This is debateable due to many benchmarks that support both sides of the debate. Bottom line is many games with 4xMSAA and 4xAA will do better on Nvidia cards and with these settings off will do better on AMD. Up to you how you'd like to play'em. At the end of the day any of the three cards your looking into will serve you nicely and give you the gaming performance you'll need for gaming.
Oh btw....Welcome to OCN Kieranloftus!
If you have time, submit your system specs in your profile so others helping you has an idea of what your dealing with to help you make the best choice for your set up etc....