To be honest, I don't think it would even be close upon further consideration. The Halo series averages about a 20-25% attach rate. Gran Turismo is nowhere close to that. I mean the highest selling GT game sold about 14.5 million copies on a console with a 120 million user base? (around 8.25% attach rate)

So going back to the OP's scenario of both games being released for consoles with an install base of 50 million Halo 4 would outsell GT5 by millions.

Nearly 11 million actually (http://vgchartz.com/hwtable.php?cons[]=PS2®[]=Total&start=36527&end=37080).

Regardless, get real man. It's 2009 not 2001, and the PS3 is in last place by a growing margin every week. You're sounding Crazzy.

When Halo 3 launched, it broke records DUDE! RECORDS! They made mad profit off halo 3. ps3 sucks but GT3 for ps2 was the best racing game EVERRRRRRRRRRRRRRRRRR!

@ymeaga1n

My mistake but that doesn't change the fact that Gran Turismo games are quite capable of great sales regardless of the system's installed user base at launch. GT4 went over poorly because of its lack of online and lack of vehicle damage but they're addressing these issues in GT5 so it won't be a limiting foctor. Even with all of the criticisms GT4 sold more than 5 million copies in its first 10 weeks and 10.57 million LTD according to Polyphony Digital's site. I don't understand what's so crazy about seeing the possibility of GT5 selling more than 8.2 million in its first year, it's more than possible.

 No you don't understand and that is the problem. It does not matter if a game is multi-platform or not, your clinging onto this as if it actually means something important. People don't think "right this game is only on this console = instant buy".

People buy games for various reasons. They like the series, they liked the reviews, they liked the demo etc etc. Just because a game has sold xyz 10 years ago does not mean it will sell xyz in 2009. Most of the franchises that have released games this generation have done worse then last generation? Why? Installment base and popularity.

What you just can't seem to understand for whatever your reasoning is that Gran Turismo 5 HAS TO SELL 9.2 MILLION UNITS WITHIN 15 MONTHS TO JUST BE EQUAL WITH HALO 3. I had to write caps because you seem to be missing that point.

So for it to be EQUAL means the game has to sell the SAME amount as GRAND THEFT AUTO 4 AND METAL GEAR SOLID 4 COMBINED ON THE PS3. Those are the games competitiors on the PS3. What happens on the 360,Wii,Saturn,Amiga 500 has nothing at all to do with the PS3. The game HAS TO BEAT GAMES ALREADY OUT FOR THE PS3! That means to MATCH Halo 3 sales it has to sell MORE units then the current number 1 and number 3 selling games on the PS3 COMBINED.

IMPLYING that Gran Turismo is a BIGGER game then those FRANCHISES COMBINED.

Which it is NOT.

Lets break down the sales to shut you up once and for all because it is clear you won't let the fanboy view drop.

Gran Turismo Sales are as follows

GT1 = 10m in 12 years with more then 20m consoles to sell to.  GT2 = 9m in 10 years with more then 20m consoles to sell to.      GT 3 = 14m in 8 years with more then 100m consoles to sell to.  GT4:Prologue = 1m in 6 years with 120m consoles to sell to. GT4 = 9m in 5 years with 120m consoles to sell to.  GT5:Prologue - 3m in over 1 year with 18m consoles to sell to.

So basically your saying GT5 will sell over 3 times more then what Prologue has in a year. Your saying GT5 will sell more then what GT4 did in 5 years in just 1 year. Your saying the opening weekend for GT5 will be AT LEAST 3.8m units to match Halo 3 sales opening. Your saying GT5 will be 4.5m more units ahead of Grand Theft Auto 4 by the end of its first year. It will sell the same amount as GT4 in a year with 100m less consoles to sell it to. Man i can keep going?

Stop dreaming. Gran Turismo is not a Mario game, it is not a novelty game with a board that does lots of other things, it is not a Pokemon game, It is not a Grand Theft Auto game. The last Gran Turismo game to break the 10m bracket took almost 8 years to do that. And you think it will do that in a year?! On a console with 100m less people?!

And you call that "likely"?

I wonder how many people agree with you that GT5 will have sold 9.2m by its 15th month?

Hyruken, please stop LOL. This is worse than watching Jon Stewart destroy Jim Cramer last week.

Also, what you have to realize is that Fanboys are the only race in the universe that don't consider math a universal language. Numbers are irrelevant when you just close your eyes and believe!

Did you forget Gran Turismo 3?

http://www.vgchartz.com/games/game.php?id=886&region=All

@Hyruken

Drop the fanboy insult, I'm not a PS3 or GT fanboy. Get that fact drilled through your skull. GTA4 being multiplatform affects sales for the PS3 version, anybody should be able to figure that out. If GTA4 were a timed exclusive for the PS3 it would have sold considerably better, that's just common sense. GT has been, currently is, and will always be far more popular than MGS. Mentioning GT5: Prologue, GT4 was more than 6 times as successful as GT4: Prologue and GT4 achieved more than half of its lifetime sales in 10 weeks. 8.2 MILLION SALES IN 12 MONTHS IS NOT UNREALISTIC FOR GT5. I can be needlessly obnoxious too. Why do you keep saying GTX sold X in X years? Games like GT receive more than half of their lifetime sales in the first several months, it doesn't take years for GT games to move millions of pieces of software. What does yhe PS3's user base have to with anything? GT3 launched with a significantly smaller user base.

the world would esplode...