Just to give some details on this.
I have a CECH 20xx ps3. It has Cfw on it and was over heating. About 1 minute after turning on it was hitting 85°C on the Cpu (Cell Chip on board) and Gpu was 59° (REX chip on board) and would shut down due to overheating. So I took it apart, cleaned all the dust out (Very little) and put new thermal paste on top of the heat spreader and new thermal pads.
Waste of time. Same results.
I had to De-lid the Cpu with a painters knife (workers extremely well) and put new thermal paste on.
Temperature is 58°C now on Cpu and Gpu is the same because I didn't go near it.
When delided don't scrape the silicone sealent off the chip base itself but clean it of the IHS and the new thermal paste will hold it in place fine if you are careful when putting it back together.
Also for note there is no smd resistors on the Cpu So you don't have to worry about knocking one off when deliding but be careful not to scrape it as damaging the traces will break it.
The thermal paste I used was MX-4 for under the IHS and on top off the IHS.
Hope this helps someone.
