On 09/29/2009 08:27 PM, Linuxguy123 wrote:
My laptop has 4GB of RAM. It is currently using only 3 GB of RAM. I
want to upgrade to 8 GB of RAM.
I am currently using a 32 bit non PAE kernel. How do I change to using
a PAE kernel ?
What difference in speed will I notice in doing this ?
Thanks
Think of dual port memory like striped disks on a super fast
controller. Performance is doubled.
Think of a PAE kernel as concatenating each memory stick. Each read to
N+1 must read THROUGH 1. It is slower, but not twice as slow.
This is a gross oversimplification, but the principle is correct.
The fact remains, that memory reads above the PAE watermark will be slower.
The fact remains that kernel, application, and user memory reside below
most caches, meaning that your cache buffers may suffer slightly, but
its still way faster than reads to disk. It also means that if you plan
to run a very large application space above 3GB, you should really move
to 64 bit. That is what it was designed for.
PAE is/was intended as a (truly miraculous) stopgap measure until users
are able to move to 64bit. Only MS dragging of their feet has prevented
this move from happening many many years ago.
Every other CPU arch used in general computing moved to 64 bit in the
early nineties (SPARC, HP, IBM, etc). In fact, HP bet the CPU bank on
Titanium, and because MS backed out (They couldn't get Windows Server to
stabilize on it, and if you ever tried 64 bit XP then you already know
what happened there), HP lost the whole game. Think about it.
Once again, I am not trying to rewrite history, just offering some
google fodder for ya if yer interested.
Good Luck!
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