Hi
i'm using Fedora 4 with custom 2.6.16.18 kernel on a Centrino Laptop with 512MB of RAM.
The problem is that SOMETIMES in performance monitor I see I have 256MB of phisical memory instead of 512 (e.g. 216 used + 5 free + something else for the video card = 256). Other times everything works fine.
Could it be defective RAM?
thanks
Nicola

if you run 'top' do you get the same stats?

Yes, same stats ...
I had also some problems booting up, that means that power was on, but the screen was off, and the pc apparently wasn't doing anything (no disk operations ...). To shut down I had to press power on for 4 secs...
I had to boot up like 6 times before it worked
It's the second time this happens. Maybe it's all related?
Some hours ago, I was working with the pc for a couple of hours, and I had no problem at all (btw, top and performance monitor both showed 512 MB)
Thanks for the reply
Help!
Nicola

I found out that the BIOS is reading 224MB of RAM - so I think it's a physical problem ...

Sounds like the computer might have taken a smack and the memory is/has come loose.

Lazlow

I thought so, I tried exchanging the ram chips (2x256), but still 224 MB in bios ...
Aaargh!

how many memory slot do you have? try to use the other ones.

I suggest you try a memory test, like the one at memtest.org.
Otherwise, could it be your graphics card taking away memory from
main memory?
If all this doesn't help, what amount of memory do you have when
you boot with a live cd like Knoppix?

Install just one memory stick at a time. Boot and see if the proper amount of memory is being shown. If one or the other shows short, you have proved that particular stick is bad. SOMETIMES you can rub a pencil eraser over the contacts of the bad memory and remove something to get the memory working. If neither show bad you may have a bad slot in the machine (not good). If you have more than 2 memory slots in the machine try some of the other slots. If you run memtest you want the version that you boot to. It allows you to look at memory that gets hidden if you try to run it a from modern os. Run it for at least a couple of hours (if no error is found right away). I had 1 stick that would not fail until at least an hour had passed (real PITA to trouble shoot).

Have fun

Lazlow