11 replies to this topic

[Haggis]

Hey Guys

I just got 4gb RAM for my laptop it did have 2gb so looking for a difference here

especially once i get my SSD (which i have now chosen)

Will Linux (Fedora Specifically) use all 4gb of RAM (give or take the ram the Graphics uses)

Or do i have to do something fancy to make it use it all?

[Intrinsica]

I thought the RAM issue was only an OS issue in that if you were running a 32-bit OS then it could only support up to 4GB? I thought it was a universal rule, not specific to one OS?

Of course, a 32-bit OS or a 64-bit OS is then dependent on what the board supports, no?

Maybe I'm completely wrong, it's been a while since I've delved in to that area of computing.

EDIT: Oh, and so I think the answer to your question boils down to which version of the OS you're using, 32-bit or 64-bit. If you have 64-bit then you can put more than 4GB in, 32-bit and you're restricted to a maximum of 4GB.

[Max Norris]

Haggis, on 27 December 2012 - 15:33, said:

Will Linux (Fedora Specifically) use all 4gb of RAM (give or take the ram the Graphics uses)

My Fedora is super rusty, but if you're using the x86 flavor, last time I used it (not remotely recent) you had to manually install the PAE kernel, something along the lines of "yum install kernel-PAE".. but like I said, rusty. (Or just use the x64 version.) I'd get a second opinion.

[Aergan]

Depends on your BIOS/Chipset configuration for 32bit OS. 3.5GB minus any shared video allocation for non Physical Address Extension, 4.0GB minus any shared video allocation if PaE is enabled.

For 64bit OS, it will use whatever is available minus any shared video allocation unless you have some early (HP, Packard Bell) Intel Core 2 era chipsets which top out at 3GB-3.2GB then allocate every/anything else to video.

[Haggis]

Its a 32bit CPU i have will check for PAE

[Haggis]

ok now i am confused

in this screenshot this shows my system info



i always thought i had a 32bit cpu

but when i look at this page

http://ark.intel.com...Hz-FSB-Socket-P

it shows instruction set 64bit

so am i right in saying i have a 64bit cpu??

how else could i check

[Max Norris]

"cat /proc/cpuinfo", if I recall if you see "lm" under flags that means it's a 64 bit processor, or perhaps something like CPU-G (a CPU-Z workalike) should tell you everything you need, but yea it does look to be a 64 bit processor, you got your options then of x64 or x86 with PAE.

[Aergan]

OS is listed as i686 which would indicate 32bit OS.

T3400 is 64bit compatible according to Intel.

Quote

Intel® 64

Intel® 64 architecture delivers 64-bit computing on server, workstation, desktop and mobile platforms when combined with supporting software.¹ Intel 64 architecture improves performance by allowing systems to address more than 4 GB of both virtual and physical memory.

[Intrinsica]

Haggis, on 27 December 2012 - 16:27, said:

how else could i check

Put in more than 4GB of RAM and see if the system recognises it.

In fairness, i686 should mean that you're running 32-bit from what I've been able to find.

[Haggis]

yeah i have 32bit OS on there as i thought it was a 32bit CPU but the motherboard can only take 4gb ram max (this is an older laptop)

I will put the 4gb in and see how the os handles it and put 64bit Fedora on there if needed

[xorangekiller]

Max Norris's 'lm' flag suggestion above is correct. That will allow you to check whether your CPU is 64-bit regardless of whether you are running an i686, or AMD64 build of Fedora. You can use the command below to check your CPU info:

echo -n "AMD64 Capable: "; cat /proc/cpuinfo | grep -Eqs '^[F|f]lags.+:.+ lm .+$'; if [[ $? -eq 0 ]]; then echo 'true'; else echo 'false'; fi

[Haggis]

yep i have the lm flag so if 32bit does not use all 4GB then i will install 64bit fedora