I am running Planetside 2 in some areas with low FPS, in some others areas with medium to high FPS at 1280 with low and med settings.
My specs are
AMD Dual Core 7750 2.7GHz
AMD 5770 1GB
I am planning to get a Phenom II X4 945. This should be good to get a nice performance and improve the FPS? Or do I need to upgrade the GPU?
I am no expert, but I have a 5770 Turbo that I OCd some with a PhII 965BE (OCd to about 3.6) and 4GB ram. Oh, and a SSHD. I feel like the Game plays fairly well at 1920x1080. I can see 'cloaked' snipers most of the time and my render distance is usually about 400m. Never checked my frame rate, though. I do get occasional lag, and in thick areas, I sometimes get the screen flicker, but that got better with a lil more CPU overclocking. My video card does not seem to be worked nearly as hard as it was in Guild Wars 2.
Based on my observations, I think upgrading your CPU will give you the most benefit, but the 945 may still not make it perfect.
For me, I am upgrading to a Radeon 7950, adding 4 more GB ram and will probably have to optimize my CPU OC to make it run real smooth. They say they are working on optimizing their engine to make our CPUs run it better, too. We will see. I have seen an improvement in stability since release.