First off, let me say I that I'm working as a computer technician. This doesn't make me foolproof, but you can use in-depth terms when posting.
CPU: Intel i5 4570 (Gen 4)
Motherboard: MSI B85I / ASRock H85I / MSI H85I (Format: Mini-ITX)
RAM: 2x 4GB GSkill Sniper
GPU: XFX RX480 Reference
SDDs: 1x 256 GB Samsung Pro 840, 1x 1TB SSD Samsung EVO 240
PSU: beQuiet 450W
Ever since I build my new system I'm having constant problems with RX480s. After my initial build was up and running I noticed that the GPU-Fan (XFX RX480 Reference model) produced a noticeable noise, sounding like an HDD or a cable hitting the fan. Slowing down the fan with my fingertip confirmed this. Since this is a reference card and I have a quiet neat cable management, there is no cable hitting the fan.
So I thought to myself: Maybe it's just the fans bearings. I RMA'd the GPU and bought another one, this time a Gigabyte RX480 (Also reference model). The issue persisted. I then RMA'd the Mini-ITX motherboard. Maybe it was putting too much voltage onto the fan or something, so I gave it a shot.
This continued and currently I have tested three RX480 (XFX, Gigabyte, another XFX) and three Motherboards (MSI B85I, ASRock H85I, MSI H85I), every combination producing the noise. At my nearest computer store (where I bought the current XFX) the vendor confirmed this issue and tested the card on a standard-size ITX board. The noise was gone. It seems that RX480s have some sort of incompatibility with Mini-ITX boards. XFXs support doesn't know anything about such issues and redirected me directly to AMD since it's a reference model.
The noise starts as soon as I power up my system, even if I only start the UEFI BIOS. I can conclude that this isn't a driver problem. I am using the latest drivers (Crimson 16.10.2), so the issue about drawing too much power shouldn't be an issue, too. My reseller already told me that a full refund won't be possible since the card has already been used. The only thing he could offer was to RMA the GPU another time and hope for the best.
I hope this issue has a known fix or we can find a selotion, otherwise I won't be able to continue playing with my RX480. I really like AMD and don't want to turn to the concurrence, but this buzzing is driving me nuts.