Video Analysis: GTA IV

I remember it as if it were yesterday. In early May last year, I spent the best part of ten days putting together the Grand Theft Auto IV face-off for Eurogamer. It was the first time Iíd put into practise the notion of slowing down video enough to all-but eliminate macroblocking and thus produce streaming video comparisons that actually work.

It was also the first time that I publically unveiled the tool used in-house for measuring frame rate on console games. Previously Iíd used it to back up my own observations (perception is a funny old thing) but this was its actual debut in terms of complete analysis on a set number of clips. Since then, the tool has been tweaked extensively, but as I had a spare day over the weekend I thought it would good to go back to the game, put together a few comparison clips and also factor in the PC version of the game, which I picked up a couple of months ago from UK supermarket chain Morrisons for a paltry 9.99 GBP (about 14 USD). I even got SecuROM installed on my PC for free!

Hereís the comparison then. The normal Xbox 360/PS3 footage, but Iíve also included frame rate analysis from the PC version - auto-configure options set on a machine running a 2.4GHz Q6600 quad core CPU, 4GB of RAM, a top-of-the-line nVidia GTX295 all running 32-bit Vista Ultimate at a resolution of 1920◊1080 at 60Hz. Yes, we do expect smooth 1080p on a high-end PC!

GTA IV... performance as expected on console, but PC is somewhat haywire.

Green line is Xbox 360, vertical green lines are torn frames (360 only), blue line is PS3 and the debut red line is PC performance on the same clips. Four clips in all, the majority of the video being the intro sequence, which shows many aspects of the engine and will be like-for-like cross platform.

Performance on console remains pretty much as I remember it. Xbox 360 still has a 720p vs 640p resolution advantage over PS3, and frame rate speaks for itself - with a 10% to 20% variance in favour of the Microsoft platform. What is intriguing is that the Xbox 360 engine seems to be switching to updating between 1VBL and 2VBL (essentially swapping between 30FPS and 60FPS modes in a split-secone at any given point) hence why sometimes - rarely - youíll see frame rates in excess of 40FPS. Note the screen tear on the 360 version. As the frames that are torn are (typically) so widely spaced apart, with the tear usually occuring at the top of the screen, the phenomenum is barely noticeable. As it is, across the clips here, 5% of the frames are torn.

The PC version proved to be an immense disappointment. Frame rate is clearly superior to the console games, but the fluctuations in refresh rate are horrible - the graph, which averages a set number of frames, doesnít really do it justice. GTA IV only uses one of the GPUs inside the GTX295, but no way are you able to manually set everything to high settings and still retain a decent frame rate. Not even on a gaming PC like mine which has GPU power way in excess of the average. The crazy thing is that downgrading to 720p and again using the auto-configure tool tweaks the other settings to the point where - often - the 1080p frame rate performance is better.

The only saving grace is that there is an option to cap refresh rate at 30FPS or lower, which should - in theory - stabilise performance. But look at the reality here - an 800-900 GBP PC should be wiping the floor with a 129 GBP console in every single regard, but it isnít. Iím either going to need to spend a lot of time tweaking settings, or I could just settle for the default Xbox 360 experience. Worst of all is the texture workÖ clearly optimised for 720p and looking very blurry in 1080p cut-scenes.

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