For all of you worrying about the CELL, about deliding and all that jazz, just down, dont dare unless you want to risk a brand new board.
Your main concern should be the RSX, not the CELL, the RSX its the most sensitive chip of the entire unit, and to mantain it properly it needs to be under 70ºC or else in the long term high temperature, the underfill that connects the RSX Die to the Chip itself, gets disconnected, thus leading to YLOD, and reballing wont solve anything, all the GPU Chips work on the same principle, and these Nvidia Chips are the most shady chips of them all.
On the contrary, the CELL B/E was made for server applications, which can withstand high temperatures, without even making a nick on the chip, it was designed,much like Intel Xeons and AMD Opterons Server CPUs to run 24/7h on a condensed shell, do dont worry about getting 70/79ºC on the CPU,but i would advise to keep it under 80ºC,just precautions, and dont worry about the solder-joints either, with even with the CPU at 80ºC, the lead-free solder needs on averege 217ºC to disconnect to the board, but if you have corroded solder-joints then reballing would solve the issue, but you would need to be 100% sure,by applying pressure to the chips on an even area.