FPS dropping after CPU change. CPU not compatible with GPU ?

[GuyMushroom]

I've been having many problems recently with my old, low-end computer

My 1st setup was:
Intel 2 Duo Core CPU
3GB of RAM
2 hard drives of 96GB capacity each
HD 7700 AMD Radeon 1GB ver. GPU

My CPU died so I had to swap it for another one so here we have my 2nd setup:

Pentium Duo Core E5300
3GB of RAM
1 hard drive of 96GB capacity
HD 7700 AMD Radeon 1GB ver. GPU

After finishing wiring and securing the connections, I decided to play some games. As of that, I found out that my frames dropped drastically. Before, I was getting about 70-120 fps on CSGO with the help of tinkering with the game commands on lowering the textures. But now with the same textures lowered I'm getting 20 fps max in CSGO.

I have not plugged in my 2nd hard drive so does it have any effect on the fps? Or is it because my CPU is having conflicts with the GPU? Also if I'm using a different RAM bar is it any different?

Any help would be much appreciated, thank you!

Re: I can't directly reply to your answers, it's because of some weird bug/glitch with the web site.
Anyways my CPU is 2.60 GHz 2.60 GHz and about 70~80C when gaming
And nope, I am certain that I'm not using CPU APU

 

[GhislainG]

What's the frequency of your CPU? How hot is it while gaming?

 

[The Hero of Orlais]

Yo may use your cpu apu, and not your actual graphic card

 

[jbonnett]

Motherboard can also be a factor here. From what I can see is that there is some information missing, the Core 2 Duo will have a model number like the Pentium e.g. E2700.

The most likely problem is the CPU frequency / IPC (Instructions Per Clock) though.

 

[GuyMushroom]

Motherboard can also be a factor here. From what I can see is that there is some information missing, the Core 2 Duo will have a model number like the Pentium e.g. E2700.

The most likely problem is the CPU frequency / IPC (Instructions Per Clock) though.

I checked and changed the motherboard. Surprisingly, it worked and the old CPU was still working. Thanks a lot for that suggestion.