When took off motherboard couple times i noticed there was serious problems with thermals with specifically CELL processor. From cold start to menu i could see CELL reaching +80C in seconds. I ended up finding couple problems and got thermals return in acceptable levels.

I recommend not to take off motherboard from the heatsinks if not knowing exactly what to do or not required and you don't need use force as after reading this article you know why or what risks there is.

Problem #1

I started from easiest which was heatsink itself. The bottom was absolutely trash so i used some sandpaper on level platform. In the plan didn't include checking was there room take off material at all and i got answer to that instantly. Nope (picture below). Put then heatsink to bench and took off little bit material round so get contact back. Result was again perfect to my own eyes.

But result was still heating up CELL. Lets go deeper and cork the IHS from top of the CELL cpu. Term for this process is "delidding". On newer superslim models CELL cpu seems to be soldered so they don't have this problem. On my own older models as "fat" IHS is hold with thermal grease and silicone around cpu. This problem may come from old grease is become hard and breaks if silicone gets expanded slightly like when you taking heatsink off and need use slight force.

Online can be found some examples but i suggest being careful and cautious as they usually speak some metal plate tool with thickness of 1.2mm max for cutting silicone but thats way too thick on my case as there was only space for 0.20mm. Other suggestions like testing metal blade against your nail does it make scracthes on your nail.. if it does it is too sharp and you may scratch your CELL cpu. Other was only let blade slide in only 10mm. The metal tool most often named was called "painters knife" but here locally thats never used term but name palette knife was what i found tool from local store. One last thing often mentioned is heating up hot CELL to loose silicone (some mentioned this as glue for some reasons...) but that is not in my mind so effective as its well KNOWN silicone has very good performance against heat. Only use some heat if you care.

I had hone blade a hair below 0.20mm so it fit cutting the silicone.

Yeah... the chip itself was clear and old thermal grease was not anymore in any good condition. Replacing grease to new and putting all back together thermals finally dropped to acceptable levels. For the end if just only problems with RSX heat do it too but i wouldn't if there is no any problems. I left it in peace.

Noticed missing heatsink fins? I throw them away as made slight trouble to put sink to bench holding well and i got already tired instead finding better solutions. Next time then alternative solutions.