# Dell XPS 400 - Real Mem vs Actual Mem



## 00MrDanS00 (Dec 21, 2014)

To begin, thank you for taking the time to read this.

- I've got a Dell XPS 400 with a Pentium D processor running at 2.8 GHz.
- It has FreeBSD 10.1 installed, and is running a Generic amd64 kernel.
- I've got all 4 of its RAM banks filled with 2-Gig sticks of memory, which should give me 8 Gigs of RAM to play with.

However, by the looks of it that's not the case.

Both according to `top`, and if I'm reading dmesg.boot correctly, my system is only seeing about 3.4 Gigs.

I've upgraded the BIOS to it's most current level which according to Dell is A07.  The BIOS shows all 8 Gigs, however something (possibly hardware) is blocking the rest.

From the other research I've done, it appears this model only supports 4 Gigs.
http://www.crucial.com/usa/en/compatible-upgrade-for/Dell/xps-400

I'm just surprised the BIOS shows it, the OS "sees" it, but the OS isn't allowed to touch it, like a kid in a candy store with no money.

I've attached the system's dmesg.boot log in txt format to the post.
(I named the system wrong when I built it. That's why the hostname says XPS-500 instead of XPS-400. It was my bad for not reading the faceplate closer.  )


?? - Has anyone else experienced this?
?? - Does anyone have any ideas I could try to get FreeBSD access to that chunk of RAM that appears to not be showing up?


If there's any assistance you could provide, awesome!
If not, them's the breaks. 
Even if in the end I just can't use 8 Gigs of RAM in the system it'll give me an excuse to re-allocate the memory elsewhere.
Again, thank you for your time.


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## Terry_Kennedy (Dec 24, 2014)

00MrDanS00 said:


> I've got all 4 of its RAM banks filled with 2-Gig sticks of memory, which should give me 8 Gigs of RAM to play with.
> 
> However, by the looks of it that's not the case.
> 
> ...


If you do a verbose boot (from the boot options at the loader screen) one of the first things that will be printed will be the hardware memory map. That will tell us where the memory is showing up (or if it isn't). Note that a verbose kernel boot may overflow the kernel message buffer - if that is the case, text will be missing from the beginning of dmesg.boot).

Another thing to try would be to burn and boot a memtest86+ ISO (or USB stick) and see if it both detects and tests the full 8GB. If it sees it and FreeBSD doesn't, that would seem to indicate an issue with the memory detection in FreeBSD. If it doesn't see the whole 8GB either, that pretty much guarantees it is a hardware / BIOS limitation.


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## 00MrDanS00 (Dec 25, 2014)

Terry_Kennedy said:


> If you do a verbose boot (from the boot options at the loader screen) one of the first things that will be printed will be the hardware memory map. That will tell us where the memory is showing up (or if it isn't). Note that a verbose kernel boot may overflow the kernel message buffer - if that is the case, text will be missing from the beginning of dmesg.boot).
> 
> Another thing to try would be to burn and boot a memtest86+ ISO (or USB stick) and see if it both detects and tests the full 8GB. If it sees it and FreeBSD doesn't, that would seem to indicate an issue with the memory detection in FreeBSD. If it doesn't see the whole 8GB either, that pretty much guarantees it is a hardware / BIOS limitation.



Terry, thank you for your suggestions.

I made use of both.
It was when I used a memtest86+ USB stick it's becoming clear my problem is most likely a hardware limitation.

Memtest86+ starts up with no issue, however before completing the first test it first slows, then errors light up the screen.

This doesn't happen when I cut down the RAM to 4 Gigs. I tried multiple memory configurations, and a spare set of RAM chips I had laying around. The results were the same, even if I tried just going up to 6 Gigs of RAM.

The Dell XPS-400 system will only use up to 4 Gigs of RAM.

I assumed since the BIOS could see all 8 Gigs that the OS would've been able to use it. It's kind of a bummer.

This helped me get the answer I needed.
Thank you very much for your assistance.


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