HEAD TO HEAD: Veteran gamer RJ DeVera and Professional race driver Gunnar Jeanette test Forza Motorsport, the new racing fame for Xbox, agaist the world it imitates. Photo by John B. Carnett

Pulse pounding, you hit the brakes and crank the wheel, but it´s too late: The
car can´t overcome its own momentum, and you slam into the wall at 150. And
then? You stand up, go to the kitchen, and grab some more cheese puffs and a
soda.

No matter how sensational a racing game´s look and feel, it´s easier to
scrape yourself off the couch than the pavement. But Microsoft Game Studios´s
Forza Motorsport , due out for Xbox on May 3, aims to leave you physically shaken
by the experience of a virtual collision-and to eclipse other racing games as
the most realistic ever produced. The software giant devoted more than two and a
half years and the expertise of 150 employees to build Forza, digitally
describing gravity, surface temperatures, friction coefficients and thousands of
other factors that mimic the cause and effect of reality. Rather than simply
using 0â€60 times, top speeds and the standard slate of statistics available from
automakers, the designers entered each car´s physical attributes-the ingredients of performance-into a physics model that predicts how that particular collection
of parts would slice through the air and grab the road. (Forza's main
competitor, Sony PlayStation 2´s Gran Turismo 4 , can´t match its power-GT4´s physics engine recalculates 60 times a second, Forza's runs four times as fast,
at 240.)

How realistic is Forza? We decided to find out with a head-to-head
comparison-but not against another game. Instead we put it up against reality
itself, calling on the insight of a professional racecar driver and a
professional car nut weaned on videogames. We wanted to know whether Forza's attention to minutiae raises it in status from videogame to bona fide simulator.
Could someone use it to train for a race, and would that training make him a
better driver? Would it challenge nonprofessional drivers enough to convey what
it actually takes to succeed under real race conditions? Would it distinguish
between gaming skills and driving skills? And finally, is Forza an advance guard
of digital surrogates for our analog reality?

The laboratory for our
experiment: Road Atlanta, in Braselton, Georgia, 55 miles north of Atlanta. The
cars: half a dozen beauties, from a scary-fast Mitsubishi Lancer Evolution MR to
a mind-blowing 205mph Porsche Carrera GT. The players: American Le Mans pro
Gunnar Jeannette and Los Angelesâ€based RJ DeVera, who makes his living
transforming mundane Japanese imports into hot-rods-â€tuners,†as they´re
called-and whose videogame expertise made him the ideal counterpart to
Jeannette. (Forza's designers also found DeVera´s combination of skills
irresistible; he consulted on the game´s menu of aftermarket modifications.) The
result? Two days of tire-smoking, wheel-gripping, computer-frying madness.