15 apps should be nothing, with the big difference of ram between N9 and N900, it should do way better than that.

Official Video from Nokia Conversations, N900 running more than 20 apps (and counting) in true multi-tasking mode (not app switching like iOS or Symbian).


Juggling Heavy Task:


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Well, technically it only have 256MB Ram, the rest is swap/virtual memory; As with PC, we all know how bad the performance can get. It won't overload the DRAM, similar like Windows, there default settings, when use up certain percentage, it will go to/use swap memory. The "generous" amount of 768MB it's useless, as when it uses above 100MB, the device starts to lag, worst it uses up to 150MB; also depending on what's on the swap memory. The main failure maybe I would say, it seems the important/main process was somehow transfer to swap memory or something (e.g. Desktop, Multi-tasking Window, Phone, etc) because accessing to this should be at highest priority especially the multi-tasking window so that we can force to close not responding applications, but sometimes or many times, when an app is hogging the memory or not responding, the whole phone freeze or become very slow in respond (can take up to minutes to get to the Multi-tasking window).

True multi-tasking is important if we're talking about true smartphone which from the beginning, the purpose is to deliver PC like experience, true mobile computer. Of course, not everyone need it, as Glen also mentioned and N900 owners also mentioned before to others who ask about N900, no phone is for everyone, not even iPhone. iPhone is simple but that's it, it cannot satisfy users who want something more; There'll be people who want to have true multi-tasking, homescreen, etc. To each his own;
As for N9, maybe I would say it pretty much covers a lot of cateory, from simple and smooth experience, to powerful and capable device; The hardware may not satisfy people who're looking or concern with specific details on the hardware, and the camera probably may not appeal those who want amazing camera, but as the OS, probably I would say it covers pretty much area. Honestly speaking, as a Maemo owner, this MeeGo does not live up to it's capability, flexibility and features; but it delivers the smoothness, simplicity; So in a way, it can capture more type of users.

Anyway, whether true multi-tasking it's important or not, EVENTUALLY, it will become a common feature because EVENTUALLY competitors will compete to provide better features and functions, it's just a matter of who provide it FIRST, and also, who can do it better. Technology improves and advance everyday; People used to say they don't need this or that, eventually one day, the features will be provided and become common. It may not be a necessity, but it's nice to have. It doesn't hurt to have more, but it hurts NOT to have IF they can do it but decide NOT to do it, there's a difference. As I mentioned before, CHOICE, they can provide it, those users who don't want it, don't use it or give the option to turn off the feature.