I'm looking to buy an Thermaltake Smart Series 850w for my 290 crossfire as my OCZ 780W isnt enough (reboots during Firestrike benchmark). Are they any good or is it worth paying the extra £25 and going for a Corsair RM850 PSU?
How much money do you have in mind for a PSU?
The EVGA Supernova G2 850w would be a much better buy at £109.99. Fully modular and Gold rated it looks like the OEM is Superflower and has a 10 year warranty. If you want 1000w the Supernova G2 1000w is only a extra £30.