Just yesterday I upgraded my system from an i3-2120 to an i5 3550. My motherboard supported ivy bridge after a BIOS update, so everything went smoothly. I am getting good idle and load temps and the system ran Prime95 all day and night without issue.
The only weird thing is that now the CPU fan will spin really fast for a short while on bootup and after resuming from sleep. The i3 never used to do this, it just powered up to its regular speed and stayed there.
I watched to see what happens and the CPU fan doesn't start spinning immediately on bootup.. it waits a second or two then spins as fast as it can (loudly) then reduces speed and acts normally. Is this typical? Why would upgrading the CPU cause this to happen?
Edit: Motherboard is an MSI H67MS E23 if that matters.
My CPU fan has been doing the same thing since I built my new system. I have a Gigabyte GA-Z77X-UDH3 and i5-3570K (BIOS ver. F17). It's not really that annoying since it only happens on startup/wake, but nonetheless I would prefer that it didn't do it at all.