Installed 7970. Popping in speakers?

Just installed a 7970 in my system to replace a 5770. I'm now getting some slight popping sounds coming from my speakers in a cycle of every 10 seconds or so. It sounds like a slight double tapping. "tick tick."

Any thoughts on how to troubleshoot this? I'm using hdmi audio out to my receiver. Had no issues prior. When I mute the sound, the clicking goes away.

EDIT:
Sorry, system info:

MSI H81I ITX
Intel I5 4460
8gb crucial ddr3 single stick
Corsair xc600m 600w modular power supply
Diamond 7970 reference
Crucial bx100 250gb ssd

uninstalling the hdmi audio driver stops the popping. Hm. Continuing to investigate.

Okay, so it seems like my receiver is creating the popping. There seems to be disturbance in the audio signal or something. It keeps trying to identify the speaker setup. It only holds speaker connection when a continuous audio source is playing (like youtube or a song), and then it only identifies my front left and right speakers, thought I have a 5.0 setup.

This is over my head. Any ideas?

The receiver (pioneer 1222) is constantly trying to switch between pcm and dolby digital (which is just the default). I can leave youtube up with a video paused and it will stay in PCM and not click anymore. Once I close the window, it starts kicking back between the two again.

It doesn't do this with any other peripheral or with my previous video card.

Blah. Okay, fixed it. In case anyone searches and finds this threat, I used this solution:

open regedit and find
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Video\{XXXX...}\0000
( 'XXXX' means device number. There are several device number folder and u should find 'AdapterDesc' in 0000 folder which key value is 'amd radeon HD 7XXX Series'. ) I just clicked through the folders in "video" until I found the proper function (pp_sclkdeepsleepdisable).

At that '0000' folder, Change 'PP_SclkDeepSleepDisable REG_DWORD' value 0 to 1. Restart your computer, and it should be fixed.