Bought a brand new msi r9 390 8 gb graphics card and happily went about setting it up after uninstalling my hd7870 driver with DDU. Installed catalyst 15.8 beta driver and gave GTA V a try. Everything was fine and dandy with almost everything set to very high, with virtual super resolution set to 2560x1440 on a 1900x1080 screen overclocked to 75Hz. A couple of hours later, when I went to play again, I realized that the game momentarily freezes every four or five seconds for a few minutes when I start to play. This happens every time I start playing the game. It eventually goes away and things go back to normal after a while. I find that pausing the game and going into settings sometimes helps to expedite things. I've turned settings down to high/normal, disabled VSR, etc. but the issue still remains. I've also uninstalled the beta driver and went back to 15.7 but to no avail.
So far, this only happens with GTA V. Haven't had such issues with AC Unity. Must be a driver issue, right? Even though it didn't happen the first time I tried the game... The game was already installed when I switched graphics cards. Couldn't say if this has some bearing on the matter...
My rig is asrock z77 + 3570k @4GHZ w/ aftermarket cpu cooler + 8 GB RAM + SSD + HDD + corsair 650W bronze PSU.