just need clarification

i already know the answer but just to be sure, 32 bit systems can only used 3 gig of ram whereas 64 bit system can go beyond that right? so if i get a 64 bit version of linux OS, i can use all 4 gigs of ram? or does this only apply to windows? thanks

 

Does Linux even need more than 512MB?

 

it lags for me

 

As you are asking about Linux I shall ask a mode to move the thread.

 

Seems more like a Linux forum kind of post to me.

 

As far as I know, the same thing applies with linux. It's not just an OS thing it's a hardware design/architecture thing. To use all 4GB you'll need the x64. Otherwise you can get about 3.3GB. Something around in there. I've noticed it at different values so can't tell you for sure.

Please correct me if I'm wrong.

 

No, you're right. With 32bit operating systems (any OS, Windows, Linux, OSX, anything) you're limited to 32bits of address space, which is 4GB of RAM total. Some of that comes off the top to allow the machine to directly address video memory, PCI cards, memory mapping and so on, so that's where you get the 3.xxGB of RAM values. With current 64bit systems, you actually only have 40-48bits of memory address space available, but that's 2^40b=1099511627776b, or 128GB-32TB of address space. And if we need to in the future it will be a simple hardware upgrade to use the full 64bits of address space, which would theoretically be 16 EB. It won't take any new software like the switch from 32->64bit.

 

ty, my question has been answers

 

Install a 64-bit Linux OS. They are in much better shape than in the past. It seems to be improving all the time.

 

A 32 bit system can actually use more than 4GB RAM, but it's not very much good, it can't manage it as well, there are some kernel compile options enabling high memory on 32 bit.

 

That's called PAE, or Physical Address Extension. It imposes a couple-cycle penalty on every single memory access, so it really slows down machines, and it only works on certain 32bit machines. Most Pentium 4 and early computers won't use it. It typically requires a server/workstation chipset to enable PAE, or a new enough machine that you may as well run a true 64bit system instead. That said, PAE also uses a 40-bit addressing scheme so it can theoretically address as much RAM as a newer 64bit system. But the really big killer is that on a PAE system applications are still limited to 4GB of RAM each. There's no way around that, which is why PAE is usually most useful on servers and such where you can start multiple processes that each use 4GB of RAM. Basically, it's a hack, and should be relegated to the dustbin of history I should know... I used to have 5GB of RAM in 3.06GHz Netburst-style Xeon desktop.