"DiRT" from Codemasters and "Forza Motorsport 2" from Microsoft Game Studios

"DiRT" from Codemasters and "Forza Motorsport 2" from Microsoft Game Studios offer two different ways to drive very, very fast.

Racing games are one of the oldest video game genres and these two E-rated titles seem more focused than ever on realism rather than arcade simplicity.

I'm not just talking about how hard or easy it is to steer the vehicles around, or shift gears, either.

In "DiRT," for example, you can tweak the angle of the front and rear tires, while "Forza" gives players even more detailed ways to adjust performance to suit the conditions, from shocks to aerodynamics and everything in between.

I've never driven full-speed into a tree or a boulder, but when crashes occur in these games (and they will, trust me), the resulting damage offers some insight as to why.

To wit: I purposely drove off course and into a grove of trees in "DiRT," smashing out the windows and turning my racer into a useless pile of scrap metal in the process.

An ill-timed scrape along a concrete barrier in "Forza 2," meanwhile, left the side of my growling sports cars crumpled and sans the side-view mirror. Take enough damage and the cars will stop working, period.

Just which one of these two games you prefer will largely depend on the style of racing you're interested in. It's akin to the difference between mountain biking and road cycling.

For those of you who'd rather careen up the side of a mountain, "DiRT" brings off-road rally racing to a large variety of courses that mix equal parts mud, dirt, sand and tarmac.

The focus is definitely speed with "Forza Motorsport 2," where your lead foot will be stomping the gas around various paved raceways.

From a purist's view, I'd have to give the edge to "Forza" because it's just such a complete racing package. The depth of options, the smooth, gorgeous graphics and the real-world tracks and vehicles are unmatched.

It's also a rare racing game that manages to be approachable for novices yet deep enough for veteran drivers.

"DiRT" is no slouch either, but a few niggling issues including a sometimes jerky frame rate kept it from earning higher honors.

While it's far more approachable for newcomers, I found it to be, for lack of a better word, more "arcadey" than "Forza." That's going to give it limited staying power for racing pros.

"DiRT" is available for the Xbox 360 for $59.99 and Windows PCs for $39.99; "Forza," $59.99, is for Xbox 360-only.

Three-and-a-half stars out of four for "Forza Motorsport 2"; two-and-a-half stars for "DiRT."