Getting very low fps

Hello, I've got problem in Aion. I'm getting very low fps, like 9 fps in Pandaemonium, max 20 fps. even in non-crowded areas, I don't get fps higher than 20 on LOWEST possible graphics setting. I had overclocked my cpu to 4.1GHz it gave me like +10 fps, 19-30fps in Pandaemonium, 25-35fps in non-crowded areas, but, 4.1GHz is too much so I returned to original state.
Back in 2.1, on semi-max settings I was getting 75-90 fps in non-crowded areas, BUT like 10+ fps when I was on raid.

PC configuration:
CPU: Pentium(R) Dual-Core CPU E5200 @ 2.50GHz (2 CPUs)
RAM: 2GB
Video Card: NVIDIA GeForce GTS 450 DDR3 1GB 128bit (Palit)
HDD: 500GB (SATAII)
Motherboard: Palit PA221 . GeForce 7050/nForce 610i Chipset.
OS: Windows XP SP2
Internet: 4 Mbit/s

CPU Temperatures are: 43° on core #1; 46° on core #2.

All drivers are updated. DirectX 9.0c updated. No viruses detected.
Everything's normal in other games like GTA IV, Assassin's Creed I,II,III; Need for Speed Hot Pursuit, League of Legends etc...

P.S I'll switch to Win7 soon

Thanks~

 

Use the default graphics engine perhaps, I even find it better.

 

Get more RAM?

 

2 GB of RAM is too low. outy:

 

I'm already using default graphics engine, on lowest settings.

I agree 2GB RAM is not enough for VERY COMFORTABLE gameplay, but it is enough to run this game on medium settings and get 55+ fps. 9 fps isn't the number 2GB RAM should give