Mystery sound in PC, stumped

Just seeing if anyone has any suggestions for an issue I'm having that is driving me insane. I've searched around and can't find anything that is exactly my issue.

Starting probably a week ago my PC has started a sort of ticking sound very, very randomly. I do notice it happens more often when under a slight load but overall it's very random and could last 5 seconds or 5 minutes. It sounds kind of like sticking something in front of one of the fans slightly and just makes a TICKTICKTICKTICKTICKTICK sound. First thought it was one of the extra fans I put in it but I unplugged them all individually and put it under load and it still continued so if it IS a fan then it has to be either my CPU fan or one of the 3 fans on my GPU. In which case my question would be what can I do about it? Built this tower about 8 months ago.

CPU: AMD-FX 8350

GPU: Radeon Gigabyte 7870

Cooler: Cooler Master Hyper 212 plus

Mobo: Sabertooth R2.0 990fx

PSU: Corsair HX650

Do you use an SSD? Are there cables in fans?

No SSD and I've checked all of the fans and there aren't any. Was the first thing I checked. There are 8 total fans in my case I think and I'm almost convinced it's one of the GPU ones but even with my face practically in the case I can't be sure.

There hasn't been any issues otherwise, it's just a super loud noise that's freaking me out.

Do a disk benchmark (Crystal Disk) and see if the ticking starts. Could be the start of a HDD failing sooooo backup your data.

Tried that just a bit ago. HDD is fine as far as I can tell. Almost sure it's a GPU fan at this point, which I have no idea how to stop/fix.

I'd check the HDD SMART data just to be on the safe side. Check it's not throwing out some errors.

If you think its the GPU fan, next time the ticking starts, stop the fan with your hand and see if the ticking stops with it.

If the GPU is off stock design, you might be able to get a replacement fan off of ebay or you could RMA the card with a faulty fan. Alternatively you could try a third part cooler for it