Re: [gentoo-user] 2GB of RAM

[David Klempner]

* Ralph Slooten <axllent@×××××.com> [2006-06-18 12:52]:
> Today I expended my RAM to 2GB (DDR) to my workstation, as apposed to
> the initial 1GB I had. The RAm added is identical to the initial RAM.
> Without changing the kernel (2.6.16.x) I still get 1GB available, and
> digging into the kernel I found the section regarding the High Memory
> Support and Memory split.

Note that without doing *anything*, with a normal 3G/1G split, you'll
actually get 896M. Recent kernels added in a config option to have a
2.75G/1.25G split, which solves this problem; it makes sense to use that
if you have 1G of RAM.

> I did a bit of googeling, the first page I found (old) said to turn on
> High Memory Support, however a more recent page
> (http://linux-vserver.org/Step-by-Step+Guide+2.6) states to leave it off
> and just change the split to 2/2 to make full use of 2GB of RAM.

My understanding is that the performance hit from enabling high memory
support is actually fairly small; if you have more than 1G (where the
fix is unlikely to break anything) it's not worth worrying about.

> I tried both ways, but either way I get poor 3D performance from UT2004
> when I have this extra memory in.
>
> (snip)
>
> however UT2004 still sucks when playing (sluggish and screen jolts
> from time to time like I have too little RAM).
>
> Any ideas?

My guesses is, as has already been suggested, that something is messed
up with your video driver. Did you recompile it when you recompile your
kernel? Is acceleration still working at all? Do you get the current
performance issues either without the extra RAM with a highmem kernel or
with the extra RAM without a highmem or 2G/2G kernel?

-- 
David Klempner