Originally Posted by jossef
i think that getting a used phenom ii x6 would be a bit hard but ill try.
ill buy a new PSU and a used HD5850.(that's should be easy)
but i'm a bit afraid of over heating.my 5850 is about 65-70c at games.
with 5850 CF i should run BF3 on ultra with decent fps(45-50avg?)
I run 5850 CF, get anywhere between 39-80 depending on where I am on the map. Most settings on a combo of high and ultra.
Believe me a single 7850 is slower. So if you are not happy with 5850 CF you wont with a single 7850.
I would only recommend going the CF route only if you can find the another 5850 or 5870 for half the price of the 7850 otherwise you'd be better off with a single card value for money.
If you can't get a second hand Phenom II X6, get a second hand Bulldozer X6/X8 (if your board supports). They perform about the same and OC better. Ebay your old CPU to make up the part of the money.
Not sure if you read my above edits. But your main issue is RAM. BF3 uses more than 4GBs of ram. Last time I checked it was eating away more than 6GBs of my 16GB total. Not cool.