If you understand the big picture, attach ratio might be interseting but not really usefull.  When you don't understand things, its totally useless.

GT3 sold what it did before PS2 hit 80 million.  

So by your logic GT5 is set to do GT3 like numbers.

By the way Prologue is near 5 million, try to wrap that around your mind.  A 40$ demo that has maybe 5% of the content of the final game does that.  Think just how freaking strong that franchise is if it can pull that of. 

Not only that, but GT5P managed to sell more than the competition's full game (Forza 3), which is on a system with a higher install base. 

If that's not an indication that the franchise is still mighty strong, I don't know what is.

The franchise is proably as strong as it has ever been, add that GT5 will be the best GT ever.  Such massive improvemnt on the previos version has never happend. 

With Reach yahh its gonna be a great shooter but truth is there are many of thsoe, with GT5 you are getting the undispouted king.  The best GT ever by a mile.

I thought Gt3 sold was released a year after the ps2 release. If I'm not mistaken, the Ps2 at that time had a lower install base than the Ps3 today (well, this fall).

GT5 also has no competition this fall ( I think), but it seems like there's going to be a ton  shooters coming out this fall. Also: sequels tend to sell less than their predecessors on the same consoles. However halo 2 outsold halo 1, so anything could happen.

Every gt game has sold at least 10 mil except for gt2 which sold 9.3 mil. However this game was released in the year 99/00 right before the gt3 & Ps2 came out which cold have prevented it from hitting 10 mil. I think GT4 could have sold slightly more if the 360 wasn't released shortly after it released. With GT5 being the Ps3's first gt and no new consoles or gts coming out anytime soon, I think it should outsell Halo.

The best selling halo ( halo 3) was released when everyone needed a halo to play. Also The Ps3 was basically a joke a that time. The 360 was the more popular console. Today, however, the ps3 has gathered momentum is more popular in most countries and people need a GT game. With halo: odst just released last year, I think a lot of people may think halo: reach will be a very short game . I know odst wasn't a real game but be honest, most gamers are uninformed. Most of them don't read gaming news, read gaming magazines, or stuff like that. A lot of gamers make their decision based on what they see when they watch commercials and when they see the box arts. A lot of them won's see a number in the title and they won't think it's a full game. Halo will sell good but I doubt it'll outsell gt5. I'm    70 % sure it won't. : ).  I'll be buying both, but if I had to choose one, i'll choose GT5 with no regret

A large portion of sales also depends on marketing and stuff like that. 

Reason for that is GT5 is not just about  racing  but about cars. With the exception of Forza 3  most racing sims focus on racing cars more than street cars. Gt series is about driving the cars you own or like to own and race them.

Grand Prix 3 V 6.4 is possibly the greatest F1 sim I've ever played aside from Rfactor V7.9.

Yeah Grand Prix 3 v 1.1 on release was pretty lame, especially in the ability ( or lack of ) to develop your car from race to race in a tuning aspect. As PC got more powerful over the course of the 2 years after Grand Prix 3, the updates made that game an amzing F1 experience. Far better than Grand Prix 2. 

With PC it's no good just talking about a game as x, y, z. There are so many versions of the same game. Many almost changing completely. 

But yeah Grand Prix 3 V 6.4 I would choose over anything.

I guess there's different strokes for different people. While Gran Prix 3 v6.4  was indeed good, I guess at that time I was too burned out of GP3 that I just jumped ship to Gran Prix 4 and still played Gran Prix 2, there's still a very active community surrounding GP2, with online hot-lap championships still being done in F1mania.net (the GP community is far more active on GP2 than GP3). 

GT5P sold so well, because people were sick of waiting for GT5.

Look it up, there has never been another GT Prologue game that was released so much earlier than the full game.

Also you're comparing a game that has been out for over 2 years to another one that has been out for about 8 months...

GT series is still strong, but GT5 Prologue isn't an indication for anything.

The fact is that GT5P is a (glorified) demo.   And it still sells this well, even though people knew full well the full game was coming (even if no one knew when, at the time.).

Forza might not have been out for as long as GT5P, but again the point is that a Glorified Demo such as GT5P sold this well even compared to a full entry in the direct competing franchise. 

My point being that GT is still a very strong franchise and has not lost its appeal, unlike what many here tried to suggest

Halo marketing /thread

But on a serious note though,  Halo has become more and more popular with every installment except for ODST which is a an expansion, it even has Halo 3 in the name. The 360 install base is more than doubled when Halo 3 came and while bigger install base doesn't necessarily mean more sales. Just look at MW2 the only reason, i repeat, ONLY reason, why it sold faster than Halo 3 did on 360, is because the install base was bigger. So yes Halo Reach will sell better (and faster) than MW2 did for 360, which will put it at least at 11 million units within a year and like 14-17 lifetime, can GT5 beat that? Maybe, but i doubt it.