[CentOS] To PAE or not to PAE...

Thu Jul 22 21:43:32 UTC 2010
JohnS <jses27 at gmail.com>

On Thu, 2010-07-22 at 17:33 -0400, ken wrote:
> On 07/22/2010 02:39 PM Hakan Koseoglu wrote:
> > JD,
> > On 22/07/10 10:25, John Doe wrote:
> >> I was wondering if anyone would know the cons of running a PAE kernel...?
> >> I have a 4GB pc and was wondering if it was worth going the PAE way to gain
> >> those exta 700MB...
> > You should use 64 bit if possible but if you're seeing 3.2GB, it's more 
> > likely that your motherboard is not capable (I have one of those here 
> > right now).
> > 
> >> In the past, I heard that these 700MB were normally reserved for bios or chipset
> >> stuff...
> > It still is, even with with 64 bit. If your motherboard supports 
> > remapping this memory with 64 bit you can use the whole 4GB. Otherwise 
> > you're limited to 3.2:
> > 
> > hakan at photon:~$ free -m
> >               total       used       free     shared    buffers     cached
> > Mem:          3262       1972       1290          0        103        737
> > -/+ buffers/cache:       1131       2131
> > Swap:         7812        308       7504
> > hakan at photon:~$ arch
> > x86_64
> 
> I'm trying to catch up...
> 
> Is the 737M cached (in the output above) what is reserved for bios or
> chipset...?  and what is gained back through remapping?
---
If you would look at my prior post you can actually see it as in whats
used.  It is 2GB of ram on 12GB capability.

Run "dmesg | grep Memory" on your machine to see it.