Thanks for the PSU answer, much appreciated. And, sorry if I'm being dense, can I expect all HD 7850 cards (or other models for that matter) to share the same measurements ? Card sellers and manufacturers don't always think to mention them.
The Antec earthwatts 380w would be fine to power a 7850. A 1GB 7850 would be fine if you're gaming at 1080p.
Another GPU / PSU question for you knowledgeable folks : I have an HD 5770 that I'd consider replacing with a 2 Gb HD 7850. The case I have isn't very big (it's an Antec NSK4482B) and uses a 380W PSU Earthwatts Green PSU. Would the HD 7850 fit in, size and power ?
You would be much better placed to measure the length and height of card that would fit in your case than us.