Strange GPU fan problem

[Robbo]

I've just put my computer into a new case earlier today. Everything else is fine, but I have a strange problem.

My card is a ZOTAC GTX 770. Since moving it to the new case earlier, one of the two fans is not spinning, or spinning slowly, then suddenly speeds up to max RPM every 10-15 seconds or so.

This is when the PC is idle, nothing is happening, the load remains and shows as idle, etc, but the fan:

I've left Unigine Heaven running for an hour and the temps didn't seem too bad and there were no artifacts or issues. It does this even when Windows isn't loaded and it's sat on the BIOS screen, so I don't think it's driver related. I tried another card and it was fine and worked as normal. It's never been overclocked or had anything done to it.

Efforts to control the fan on Afterburner haven't worked, it does this no matter what (with varying frequency), 33%, 100%, etc.

Any thoughts? Is it knackered?

 

[Robbo]

I suppose the lack of replies indicates this isn't a common issue so I'll have to assume the card is faulty.

Tempted to get a 290X to replace it (unless it gets swapped).

 

[Robbo]

I've had a look as best I can, and the connectors (that I can see) all seem to be connected properly. I could take off the entire heatsink for a better look but I don't want to break/void anything.

 

[Robbo]

Yeah, I'll send it back, it's not a problem. Cheers!