Maybe I can save someone else the trouble I went through.This CPU works well, not for gaming but for general use, and is a great value, but the stock CPU fan that comes with, probably because it uses metal screws, rattles the case and sounds like a jet engine whenever under load. I used it for months, accepting it as necessary, but it slowly started eating away at my brain. I had to replace the fan, or replace the computer!Well, I ran into several issues: 1) it's a small case, so you need to buy a low-profile fan, 2) the motherboard has a metal screw mount, which no good fans use (I bought the only one I could find that used the same mount, as it was even worse!), 3) the case doesn't have a cutout to access the rear of the motherboard, or a way to remove the rear of the case, so you HAVE to remove the motherboard in order to change the mount.I bought, tried, and returned several fans figuring this all out, and there was very little on the Internet about this issue, because most cases have cutouts, or everyone who replaces CPU fans just assumes everyone else is used to removing and reinstalling motherboards, I guess.I wasn't, but it was driving me crazy, so I bit the bullet. I watched some Youtube videos, took everything apart and removed the motherboard, put in the new mount and heatsink/fan (Noctua NH-L91, in case you're curious, amazingly quiet), replaced everything - and as noobie and tech-averse as I am, it worked the first time!It took less than an hour, and my God was it worth it! I tested my computer under load, and the temp stays low and you can't tell the difference between the fan running and not running. It was well worth it. Before this, I was considering buying a new computer, it was driving me crazy - but I'm happy to report that once I replaced the fan, I'm as happy as if I had a new computer! It sounds like a new computer. And I can say that even a 50-year-old computer noob can take out and replace the motherboard on this Acer!Notes: 1) I'm pretty sure it has to be a low-profile fan because there's not that much clearance inside the case, and the RAM modules are very close, 2) you won't find many fans that fit the existing metal screw mounts, and certainly no good ones - all the good ones use pushpins, or custom mounts, which require you to remove the motherboard to access the existing mount on the backside, probably to reduce vibrating the case itself, 3) it's not that hard to remove and reinstall the motherboard, it's just a step-by-step process, and the Acer doesn't have that many wires or parts to screw up, 4) a good CPU fan only cost me $40, and I'm sure some $20 would work just as well, and 5) if the existing fan noise bothers you then replace it!