Frank Cox wrote:
On Sat, 16 Feb 2008 21:36:42 -0500
Ric Moore <wayward4now@xxxxxxxxx> wrote:
If you have 2G of memory, would using mem=2G be of any advantage?
I have 4G of memory. It works when I specify "mem=2G". It also works when I
specify "mem=4024M" but I don't get a whole 4024mb.
Booting without "mem=" causes it to run amazingly slowly.
I am reasonably sure that what happens is that you are using some
uncached memory, and that is making your system slow. There are (at
least) two possible causes, which is why I wanted the BIOS info from
dmesg and the MTRR info.
- your BIOS could be giving bad information to the kernel
- the kernel could be generating the wrong MTRR from the BIOS info
- your hardware may not be able to cached memory mapped over 4G
OK, at least three reasons. ;-)
In any case, that's the issue, and keeping the mem= small enough to stay
all cached will give you vastly better performance than more slower
memory (as you found).
--
Bill Davidsen <davidsen@xxxxxxx>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
