GTA 4 reacts so strongly to increases in graphics memory, CPU performance, and GPU performance that it's easy to constantly wonder if you're fully utilizing your expensive hardware or not. The game’s need for CPU speed is so strong that not even four cores can really satisfy it. Frame rates with a single-core CPU are so ridiculous that the game is practically unplayable. Even with two cores, GPU utilization is just 69 percent. Fewer than four cores are unthinkable for this game in our opinion.
Overclocking the CPU shows that the game just can't get enough CPU performance. To increase frame rates in GTA 4, you need at least four CPU cores, and when overclocking those cores to the max, you can start thinking about upgrading to a better graphics card. In the video settings, you can incrementally set the amount of graphics memory used by the game. This way, 768 MB can actually be enough, but as far as we could make out, only 630 MB are actually used at that setting. GTA 4 can take advantage of more than 1 GB of graphics memory, so if you like the game and play it a lot, you should definitely consider a graphics card with lots of onboard memory.
We did some further testing with a stronger AMD Radeon HD 5870, as well as two of them in a CrossFire setup. This test is meant to show you that despite the 100% CPU utilization, upgrading the graphics card still manages to further increase performance. We really like the idea of a game where the frame rates are actually increased--no matter what hardware upgrades you perform in order to improve performance. The GeForce GTX 460 is quite alright for GTA 4, but the AMD Radeon HD 5870 can handle a greater range of visual quality settings with its 1 GB of graphics memory.
In the second part of this story, we'll measure the hardware utilization in 10 more games. In addition, we'll assess overall performance, energy consumption, the effect of the CPU core count on game load times, and look at minimum frame rates before rendering our overall conclusion.
The games we'll include in Part 2 are: Just Cause 2, Kane & Lynch 2, Left 4 Dead 2, Mass Effect 2, Price of Persia: Forgotten Sands, S.T.A.L.K.E.R.: Call of Pripyat, StarCraft 2, Supreme Commander 2, and Wolfenstein.