2 Graphics cards

[Insanitypays]

So I have a Radeon HD6570 (stock with PC) (2011) and a Radeon HD4850 (1gig) (200
I read somewhere that the 4850 was better than the 6570 and im ready to pop it out and put in the 4850, im hesitant though because I dont want to accidently downgrade.

I can currrently run BF3 on medium settings with the 6570, but I want a bit of a boost here and dont know exactly which to pick if anything.

I am also a little bit afraid of my PCU, from what I know the 6570 is 2x as efficient power-wise than my 4850. I have a 300w PCU

If it matters I have a 2.8ghz intel i7 processor...

Thanks! -Echo

EDIT: I have room for a single card

[Psyrus]

According to these reviews, they're mostly equal in benchmarks, with the 4850 being *slightly* ahead

Sapphire Radeon HD 6670 and HD 6570 Video Cards Review - 3DMark Vantage :: TweakTown USA Edition

Palit HD4850 Sonic Review ? Page 15 - Testing: 3DMark Vantage - Overclockers Club

AMD Radeon HD 6670 & HD 6570 Review - Page 4 - Futuremark: 3DMark Vantage

Synthetic Benchmarks: 3DMark Vantage : Radeon HD 4850 Vs. GeForce GTS 250: Non-Reference Battle

[Pedz]

Id probably stick with the 6570, as I am not certain your PSU would cope with the extra power required for that higher GPU as well as your processor, which will use around 130W itself (dependant on which processor it is, Intels website will tell you, or CPU-Z).
Also for such a minimal performance increase the power saving is worth keeping the 6570 in. Also iirc the 4850 was DX10? whilst the 6 series is DX11, which brings nice features and some optimisations.

Another note is that even if you had the PSU and the room to cope for both cards, the series mismatch makes them incompatible from what I've read. Either that or it will reduce performance as it tries desperately to match the speed.