i already have ubuntu on my desktop.
i think i will try opensuse 64 bit

It will handle it, but you will hit the limitation that johnsfine posted-

So yeah, 32bit can 'see' more than 4GB, but it cant really use it unles you are running multipule processes.

What application might you want to run that uses more than 3GB for one process?

For a typical home user, video editing is at most a "maybe" for making good use of more than 3GB in one process. Everything else you do likely uses much less than 3GB per process even in a 64 bit Linux.

There is no point worrying about the 3GB per process limit unless you actually want to run applications that make good use of more.

Running multiple fairly big processes is more common than running any super big processes. So over 4GB physical ram is often useful even when over 3GB per process is not useful.

I will try fedora 15 64 bit or opensuse 12.1 milstone 3

Point. BTW, I've never used anything like 3GB+ perprocess, but I dont use linux for some of thing sI've seen very large amounts of RAM used with (things like 3DS max).

Aside from video editing, and nasties like #dS max, you really need to be using multipule big processes to make use of anything like 6GB. Unless I'm mistaken the OP is using a laptop, and I wouldnt suggest running mutlipule huge processes on a laptop. Besides the heat issue, laptops are quite a bit slower than desktops.

Might as well stop with 4GB unless you know you will be using huge processes, or running multipule big processes.

You realize that without the 1/3 split option in the kernel, the kernel itself will only use 2gb of swap space on a 32bit system right? If you make swap any bigger without using the 1/3 split option its just a waste, even if the kernel knows you have 500GB of swap it will only use 2gb out of it.

my swap is always 2GB,
if my RAM is big enough, i think the OS will not use swap at all.

Hi, TigerLinux:
Short answer: absolutely correct :)

Longer answer: The system *may* use swap for *other* things (for example, hibernation).

But the short answer remains: if you have enough RAM, you won't use any swap.

Nonsense. Your "address space" (e.g. 4GB for a 32-bit CPU, or 64 GB if using PAE) is *independent* of either the amount of RAM and/or the amount of swap you've got available.

Good choice - I agree :)

'Hope that helps .. PSM

I think I will choose Fedora 15,
i hope it supports my nvidia GT525M graphics card and the intel core i5 integrated HD graphics too.

"Back in the day," (yes, I remember it well... so there...) the IBM/360 (ahem...) had a 24-bit address bus. (Having "16 megabytes of memory" was inconceivable in the day when that "memory" was almost certainly magnetic core...) The entire CPU architecture was built around that (what would become a...) limitation.

Several generations of that processor architecture have followed, each one expanding upon its predecessors in a not-always-quite compatible way.

The Intel processor family has patiently followed the same course: from the 8008 to the 8080 to the 8086 to the 80286/i286 to ... the 64-bit architectures of the present day.

In every case, the single most important barricade that "got busted down" was memory capacity: how much RAM the processor could address, if it had it. Also in each case, the processor-architecture change was accompanied by a fundamentally new version of the operating system(s) in question: a version that was built for the new processor, and which required it.

Linux is simply following that same familiar course. If you have a 64-bit capable CPU, you should be running a 64-bit capable Linux version on it. Only then can you access the full range of memory that the chip is capable of addressing. And, only then are you using that chip in its "native mode."

Intel got dragged kicking and sceaming into x86-64. If AMD hadnt released that pesky x86-64 architecture, intels plans for itanium might actually have worked.

+1, and not only so you can address memory. 64bit can have quite a preformance edge over 32bit.

That souinds like an 'optimus' setup. If its optimus, fedora will not support it 'out of the box'. If you are lucky, you might be able to use the GT525M GPU, but in most cases the best you can do is totally disable the nVidia GPU.

Try http://www.omgubuntu.co.uk/2011/05/b...o-linux-users/ & post the results (please please please!). I have an optimus laptop on order and I am desperate to know if this works well enough to make my purchase worth while before it's too late to cancel!!

In my view,the differences between memory and swap space are obvious.

the cpu use the bus addressing the memory directly,and 32bit can address 4G theoretically ,but the detail amounts actually depends on the cpu and the os.
to swap space ,we can simply treat it as a subsidiary memory,and regard it as a buffer of harddisk.
when we don't have adequate memory,we can move parts of it bits into swap space fastly and move it back fastly when we need the bits.the swap space is just parts of disk,and cpu address it bits through memory,so it isn't included in the cpu addressing space.
the swap space is just a os mechanism ,the memory addressing is a cpu mechanism in general.

Chances are no, you wont be able to use the nVidia GPU at all. It depends on the model laptop you have.