So, I want to upgrade to enjoy BF3 Multiplayer with Ultra settings @ 60fps minimum. Should I stick with the FX 6300 and overclock it to ~4.6-4.8 GHz or just go for something like the 3470. For the upgrade I'd go for a MSI 990FXA-GD65, a second gigabyte 660 and a decent 700w psu. What I'm worried about is that the FX-6300 might bottleneck the 660s on 64p servers. I managed it to overclock the CPU to 4,1 GHz with the cheap MB and on a 64p TDM server the LOWEST measured fps were 43 (Ultra) and 62 (Low). On an empty server its 51 (Ultra) and 91 (Low). Will I be able to run it on 60 min with the 2 660s? Is anyone here with the same CPU paired with a higgh end GPU who can tell if it works?
By the numbers you posted, it seems that your CPU is able to go above 60FPS, so it's not your CPU that is limiting your system, it's the 660. BF3 is great with SLI, so you should get almost double FPS, I would estimate 75fps on ultra settings. But this is the point where your CPU might choke. Your best bet is more graphics power, then upgrade your CPU if it's at 100% usage.
I can't recommend SLI as I've had bad experiences. I used to have 2 x 560ti's and BF3 was choppy as hell. Went back to one and it was perfectly fine. I hope these issues don't affect you.
I just figured out that If I put mesh quality on Low I get a huge FPS boost. On a full 64p gulf of oman server with 720p, Ultra and no MSAA the minimum can go down to 36. Now with mesh quality on low the minimum rises up to an amazing 57, and that with a fairly mild OC of 4,1 GHz. So I think I'll keep the FX. What do you think how more CPU intensive will BF4 be?