I just built a new pc and I wanted to see how games would run on it before I bought a new graphics card. So I loaded up GTA IV which before I would get about 17 FPS on the lowest settings with my old pc. Now I still only receive about 17 FPS on my new pc which is MUCH better than my old one. I have an i5 2500k stock and a Radeon 5450 512mb. I know the graphics card is defiantly not the best but I assumed that GTA begin such a cpu heavy game that I would defiantly be able to run it smoothly on the VERY lowest settings, even the resolution on 800x600. I am pretty new to this so I don't know if I have to change something in the BIOS to get my cpu to work properly or if my graphics card is truly that bad.
CPU: i5 2500k (stock)
RAM: 8GB (2x4GB) DDR3 Corsair Vengeance
MB: Gigabyte GA-Z77X-UD3H
PSU: Corsair Builder Series CX 600 Watt
GC: XFX ATI Radeon HD5450 512MB
1) make sure to update GTA IV, if you haven't already. Unpatched it's pretty awful regardless of your system.
2) Your graphics card is awful, the onboard graphics on your CPU are probably better, or similar. You definitely want to look at upgrading that to anything else asap. Rest of your system looks like it has plenty of scope so whatever you can afford will probably work.
Yeah if you are getting the same FPS on both it's pretty clear that the graphics card is the limiting factor. Like I said above, your onboard graphics are maybe worth a go, but they won't be much use either.
I'm sure with a solid new card you'll be having no issues at all as the rest of your system is pretty awesome.