That is utter bullcrap. The only bottlenecks in GTA IV are your CPU and system memory. Use a 64 bit OS and have at least 4 gigabytes of good RAM, then you can play with a dualcore, fx an E6700. With less memory you will need a quad or an i7.
I am running it right now on Win7 32 with 4 (3) gigs of RAM and it still stutters often.