I can't answer all of your inquiries, however, there's a couple of CPU coolers you might like that I just have to double-check.  The Precision 3620 takes 2 different pancake coolers, one of those the same as the 9010.  Hi [NAME] de Oro , do you think this cooler will work on a 9010 MB, or will the screws not line up?  Dell Precision Workstation Tower 3620 Cooling Heatsink Fan 0VWMTJ  [IMAGE] If it works, you won't have fan error message at startup. Also:  Noctua NH-D9L, Premium CPU Cooler with NF-A9 92mm Fan (Brown) for Desktop  [IMAGE]  
Some time ago, I bought an OptiPlex 9010 MT motherboard with an i7-3770 and stock cooler. Yesterday, I changed the case so it would have more airflow. Everything is working fine. The temps are pretty good, around 75 degrees Celsius while gaming both the CPU and GPU, but the CPU cooler is running at around 2000 RPM on idle, and it gets pretty loud when gaming. From what I read, the 9010 motherboard has a backplate integrated with the CPU block(?), so the CPU gets loose when I unscrew the backplate. Also, I read that some people recommend buying CPU block protection for 115X sockets from AliExpress. I just want to change the stock cooler to something quiet and good. I bought a 5-pin to 4-pin adapter, and I don't really care about the startup errors. The max height of the cooler that I can mount is 15.5 cm. Can anyone help me with that? What should I buy and how should I mount it?
Optiplex 9010 MT CPU Cooler upgrade