- I don't really care about card branding, but I stick to brands that I know can make a good board/PCB (Asus, Gigabyte, etc). Those should be a little more durable, having more expensive capacitors, stuff like that. Performance wise they should be equal (given that clocks are the same).
Some manufacturers might use slightly better memory chips, giving a little more overclocking headroom (again, should be the same performance wise).
- CPU will always become a bottleneck with 2 cards (like the 5770).
- "XP mode" is a virtual machine that comes preinstalled (more like integrated) with XP. You can run regular programs in there, but no games; it uses a "simulated" graphics card, not the actual piece of hardware in your system. Pretty useluss imo, since you can get most software running in Win7 itself.
- I'd go with the 5850, but gaming is my top-priority.
