I have a 2012 Mac Mini, it's been slow since I got it (second hand). I recently did a HDD drive swap (as in a few minutes ago) and it's still slow. Parts Computer - 2012 Mac Mini Quad Core (non-server) 8GB Ram 1TB HDD (originally from Apple) I usually keep a drobo connected as well as a Newertek MiniMax hdd enclosure and optical disc reader. Go to the monitor through a Thunderbolt to DVI adapter, have a TV hooked up through HDMI. Ethernet cable. Battery Backup. Time Capsule sitting near it but not directly under it on a shelf below the Mini. I'm using a HDD toaster (2 disk bare drive enclosure) to do testing over USB3 and for cloning. SSHD - Seagate 1 TB SSHD Hybrid Drive Issues - Sometimes Mac Mini works fine but it often runs slow. It'll be fine, then slow, then fine, then slow again. It'll beachball as I type out words, open and close apps, etc. It's slow to reboot, and after I login there's a long progress bar to get into the Mac and start working. Troubleshooting - RAM - it's not the ram, even on a reboot it's not using anywhere near the full RAM and the swap is usually 0. OS - I've tried reinstalling the OS on top of itself in the past if I recall correctly, didn't fix anything. HDD - I ran Black Magic Disk Speed Test on the OEM Apple hard drive while it was in the mini. It varied but it was pretty slow, it'd stay at 11 MB/s write, then jump up to 40 or so, then drop back down to 11, read was similar. Ok, so swap the drive right? I tested the drive in a toaster outside of the mini and was getting good speeds for a few tests. Then I'd test it a day later and be back down to 11MB/s. SSHD - I had a Seagate 1 TB Hybrid drive that I'd been using for something else, it wasn't superfast but it was getting like 60-80 MB/s write and read consistently, sometimes higher, had no problems other than it wasn't right for a high performance setup, and it wasn't saving properly on DaVinci Resolve, which I don't think was the drive's fault based on other anecdotes I've heard. - I cloned the old drive to the new one using a HDD Toaster with a cloning function, so it should be a perfect 1:1 copy. I ran a speed test on the SSHD while it was in the toaster connected to my Macbook Pro after the clone completed, and I got around 44-60MB/s, not great but fine. I ran disk utility first aid which didn't seem to make a ton of difference. Currently - Now that the SSHD is back in the mini, the Seagate SSHD is exhibiting the same behavior as the previous HDD. It peaks out at 46 MB/s write with a similar read speed, but it spends a lot of time down at 11 MB/s. Then I test it again and it jumps up to 70-100+ MB/s read/write and behaves as expected, until it doesn't again. What could this be? Right now I'm thinking it's not actually the drive and potentially the adapter that converts the SATA plug on the hard drive to whatever little tiny plug is in the Mini's logic board. Or maybe it's a logic board issue? To me this reads as a hardware issue, but one that persists across hard drives so perhaps it's the connection? Thoughts?