Hi, I had my hands on my desk, flat, and felt this weird, light thumping. Put my hand on my computer case and felt it moreso. Opened up the case and figured it might be the hard drive doing something weird; It is indeed "thumping"(?), as if it's trying to hit the disk for information and stopping right away. Its pattern is about 1.5 seconds, and then 2.5 seconds every other hit. What's up with this? Rig specs are in the sig, this drive is not in use when this is happening (recording-only drive). Will test it at some point to see what it feels like under load.
If you can feel the thumping through the desk, it is likely worse than just the regular disk-seek movement. Don't be surprised at the idea that your disk is seeking while you are not using it; all kinds of things, even some that are not malware, will cause this.
Personally, I would immediately make a copy of the data somewhere else, then look at the SMART statistics and download and run the diagnostics from the disk mfg.
If it's the SSD that's thumping, run away as fast as you can before the monster gets out.
My guess is that the HDD is not screwed to the chassis properly and when it starts to spin up, its bouncing against the case. I have seen this type of thing a couple times when I was repairing someone's computer. If the problem is internal within the HDD, then a bearing is probably bad and the thing could freeze up or fragment in a bad way. If that's the case, do as Wyoming Knot suggested and back up the HDD and then replace it before something bad happens.
I don't use any AV and haven't for many years, however I do run the whole shabang of scans every once and awhile. Nothing ever comes up (Did get a trojan once as soon as my mom got on the computer one time, was pretty funny.). No malware to be found as usual. And I'm 100% sure it is the HD.
Well, it's in a Lian Li K62, tool-less bays.
Also, it doesn't seem to be doing it now. Weird. What would cause a hard drive to randomly decent to start seeking for things though? I could understand if it was an OS drive, however It's purely for recording purposes and wasn't being used for any reason that day when it was turned on. I'll update if it starts doing it again and see if there's any way to recreate it.