I am aware that GTA IV is poorly optimized, but I think my system should be able to handle it. No matter what settings and resolution I play on its the exact same. My system is in my signature. I get like 5 FPS, and it freezes every few seconds.
Any solution? It's not a big deal, I have GTA IV on my Xbox 360 too, but I wanted to play with mods.
I've played gta and my machine is a little less as high spec as yours but mine seems do to okay however, I have a NVIDIA card.
What resolution are you running the game in? you might have to lower it a fair bit.
However I think the problem lies with how your graphics card its ATI and gta was very very poorly optomized for ATI threads like that used to be found all over the steam forums. I suppose making sure that your drivers are up to date as always, maybe even trying beta drivers. Also try turning the settings down or to application only in the AMD Control centre. Sorry I didn't give you a sure fix but that's all I know.
I have tryed both my native resolution, 1920 x 1080, and the lowest possible resolution of 800x600 and still the same FPS. I have the latest drivers, but I suppose I could try the beta ones. Not a big deal if it doesn't work, as I said, I have it on Xbox too.
The game should run much better than that with your system. I have a Radeon HD 6870, and the game runs okay, so it isn't necessarily that the game is unplayable on AMD/ATI cards.
Make sure the game is patched to at least Version 188.8.131.52. The original release of the game was extremely buggy. You may try reinstalling the game, or verifying integrity of the game cache if you have the Steam version. It could be a bad installation.
I have R9 280X too with i5 2500k and patch 184.108.40.206, the game runs fine, same as my old GTX 560 '-'
Try updating ur game and check temps, voltage, etc..
The Graphics card is all ok. It's only on GTA EFLC/IV, ArmA 2 and Sniper: Ghost Warrior (this one is the worst. The image is black and white and upside down and I loved this game the first time I playd it) that I have problems on. On BF4 I usually get an average of 60-65FPS with everything maxed out, so the VGA is ok