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.
It's hard to say what you need. Like someone mentioned, it's not optimized. Specifically to utilize dual cores.
Run programs like CoreTemp to see the CPU utilization (or you can run the task manager on a second monitor to see the same thing). Also run MSI Afterburner and turn on the option for GPU utilization.
Compare these the utilization on your CPU and GPU. Whichever one is not at or close to 100% will tell you where your bottleneck is. In your case, neither the two are very powerful.
One thing about ps2 is some systems handle it much better than other high end systems. In my case, I get about 35 FPS in massive base battles. Some people I know are using weaker systems and getting higher FPS. I'm using an i5 3570k and a 680. Your milage may vary.
After a lot more research on this issue, it looks like RAM quantity and FSB/RAM speed are what trigger the 'CPU' bottleneck. Some players report having the 'CPU' show up as the slow part in the FPS screen, but their monitoring software shows the CPU usage as around 50%. It seems you can also get a big improvement by going into the useroptions.ini and decreasing the render distance to about 1000. Search for Planetside 2 ini recommendations, there are a lot of good tips out there.