Is there a of trade-off between number of leagues/potential length of game?

As per title, is there some kind of trade-off between how many active leagues you can have, and how many seasons you can go before things start to really slow down? (I think I read that that's what can happen.) I ask because I've just ordered a new laptop, and I'd like to run a behemoth of a game with looooads of leagues running, but I don't want it to slow to a crawl come the end of the third season or something silly like that. (The laptop is a 2ghz duo 2, with 4gb DRR3 RAM, running Vista, specifically.)

Doesn't each season become slightly slower than te last, I think someone did an experiment with FM08 and it was something like 3% slower each season.

Oh right, so no matter how many leagues you've got running, it'll still get slower by pretty much the same rate each season?

What's the "dangerously low on memory and will be shut down" thing I've seen people mention, or rather, do any tech-heads know rough numbers of leagues/seasons before I may see it?

4gb is more than enough to play with many leagues without running out of memory. Unfortunately there are no CPUs on the market and will not be for a quite a few years that are able to run FM with more than a few leagues loaded. Unless of course you are very patient person and think that waiting a few minutes just to get to the next match is acceptable. SI are seriously underestimating the importance of speed. Amazon i think has done some testing and they found out that even half a second of additional delay causes massive drop in revenues. And here we have a game that doesnt make you wait half a second for the next move, but minutes on top of the line machines that most people dont even have.