Im using my Microserver Gen8 a lot and, sometimes the poor performance of the CPU is noted (when showing galleries with many images for example). So I decided to replace it by another better one.
CPU model to choose
I chose the cpu model based on this resource
Those are compatible CPU with different performances prices and all of them with low power (so it does overheat). Altough I bought E3-1260L model with a price of 47$, I received the E3-1265L and a refund of 5$ (no problem).
It also came with some thermal compound (otherwise i would have to buy it because its neccesary)
Before upgrade temperature
Open the chassis cover and start unplugging those cables that can avoid extracting the mainboard. Maybe you didnt need to use the same cables as I show in this images.
Pull from those points to start extracting the mainboard cautiously
And simply revert the steps to finish this procedure.
Check CPU is detected
Disable Turbo Boost
Probably you have the Turbo Boost enabled. I prefer not to overclock the CPU to avoid overheat. You can disable it in: System options -> Processor options
After some time working with the new CPU, check the temperature and ensure all values are correct