problems with 1gb ddr memory sticks on linux
I have a box running Debian 3.0 with a Via C3 800mhz processor that slows to a crawl when I put in a 1GB stick of PC2100 DDR memory.
The board, a Gigabyte GA-6RX, supports this memory stick.
My 2.4.18 kernel is compiled with High Memory support and linux and the bios see all of the memory. However, the box is VERY slow. It takes about 5 minutes to install .deb binary. It took me 12 hours to compile the 2.4.18 kernel!
Here is what I have done to rule things out . . .
1) The box runs FAST with M$ Windows 2000.
2) The box runs FAST when using identical kinds of memory but in quantities of 512MB or less.
3) The box runs slow with other linux distos also. (I tried Redhat 7.2)
It seems to me that the problem has something to do with the linux kernel and 1GB memory sticks. Am I off base?
Anyone have any ideas?
Thanks,
Bryan Walton
Quoted 5 lines · Bryan K. Walton
I have a box running Debian 3.0 with a Via C3 800mhz processor that slows to a crawl when I put in a 1GB stick of PC2100 DDR memory.
The board, a Gigabyte GA-6RX, supports this memory stick.
Could it be the case, that it really doesn't support that memory eventhough it claims to?
Quoted 2 lines
My 2.4.18 kernel is compiled with High Memory support and linux and the bios see all of the memory.
Did you try without High Memory support?
Quoted 9 lines
However, the box is VERY slow. It takes
about 5 minutes to install .deb binary. It took me 12 hours to compile the 2.4.18 kernel!Here is what I have done to rule things out . . .
1) The box runs FAST with M$ Windows 2000.
2) The box runs FAST when using identical kinds of memory but in quantities of 512MB or less.
Did you try with a total of 1024MB on two 512MB modules?
Quoted 4 lines
3) The box runs slow with other linux distos also. (I tried Redhat 7.2)
It seems to me that the problem has something to do with the linux kernel and 1GB memory sticks. Am I off base?
Try the "slow" memory and use a mem= boot option to tell the Linux kernel not to use all of it.
Quoted 2 lines
Anyone have any ideas?
I wonder if it could be the case, that it for some reason doesn't use cache for all the memory.
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Quoted 7 lines · Bryan K. Walton
1) The box runs FAST with M$ Windows 2000.
2) The box runs FAST when using identical kinds of memory but in quantities of 512MB or less.
3) The box runs slow with other linux distos also. (I tried Redhat 7.2)It seems to me that the problem has something to do with the linux kernel and 1GB memory sticks. Am I off base?
Almost certainly a BIOS problem. What typically happens when you see this is that the BIOS misconfigured the MTRR registers. Linux starts from top of ram windows seems to start from bottom so the effect shows strongly in Linux.
Can you post your /proc/mtrr file please
Quoted 8 lines · Alan Cox
Almost certainly a BIOS problem. What typically happens when you see this is that the BIOS misconfigured the MTRR registers. Linux starts from top of ram windows seems to start from bottom so the effect shows strongly in Linux.
Can you post your
/proc/mtrrfile please
Here you go . . .
Dimm slot 1 = 256MB DDR PC2100 and
Dimm slot 2 = 1024MB DDR PC2100
and the /proc/mtrr shows:
casa:~# cat /proc/mtrr reg00: base=0x00000000 ( 0MB), size= 512MB: write-back, count=1
Thanks,
Bryan
Followup to: <[email protected]> By author: "Bryan K. Walton" <[email protected]> In newsgroup: linux.dev.kernel
Quoted 12 lines · Alan Cox
Quoted 8 lines
Almost certainly a BIOS problem. What typically happens when you see this is that the BIOS misconfigured the MTRR registers. Linux starts from top of ram windows seems to start from bottom so the effect shows strongly in Linux.
Can you post your
/proc/mtrrfile pleaseHere you go . . .
Quoted 8 lines
Dimm slot 1 = 256MB DDR PC2100 and
Dimm slot 2 = 1024MB DDR PC2100and the
/proc/mtrrshows:casa:~# cat /proc/mtrr reg00: base=0x00000000 ( 0MB), size= 512MB: write-back, count=1
Your BIOS didn't mark the second memory chunk as cacheable, so you're running it uncached. No wonder it sucks.
-hpa
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Quoted 7 lines · Bryan K. Walton
Dimm slot 1 = 256MB DDR PC2100 and
Dimm slot 2 = 1024MB DDR PC2100and the
/proc/mtrrshows:casa:~# cat /proc/mtrr reg00: base=0x00000000 ( 0MB), size= 512MB: write-back, count=1
Your BIOS misconfigured the memory control registers. You may find swapping the DIMMs over fixes that or a BIOS update. If you don't want to update your BIOS then doing
echo "base=0x00000000 size=0x60000000 type=write-back" >/proc/mtrr
should override the BIOS setting and make your machine speed up.
Many thanks to Alan, Mark, and everyone else who offered advice on fixing my problem with my bios and large memory sticks. I rewrote the /proc/mtrr and everything is speedy now!
Thank you!
Bryan
Quoted 7 lines · Mark Hahn
Quoted 4 lines
echo "base=0x00000000 size=0x60000000 type=write-back" >/proc/mtrr
should override the BIOS setting and make your machine speed up.
don't mtrrs still have to be a power of two in size? ie, he'd need two for 1024+256...
You are correct he should add one starting at 0 for 1Gb and one at 1Gb for 256Mb - my error.
Quoted 16 lines · Bryan K. Walton
I have a box running Debian 3.0 with a Via C3 800mhz processor that slows to a crawl when I put in a 1GB stick of PC2100 DDR memory.
The board, a Gigabyte GA-6RX, supports this memory stick.
My 2.4.18 kernel is compiled with High Memory support and linux and the bios see all of the memory. However, the box is VERY slow. It takes about 5 minutes to install .deb binary. It took me 12 hours to compile the 2.4.18 kernel!Here is what I have done to rule things out . . .
1) The box runs FAST with M$ Windows 2000.
2) The box runs FAST when using identical kinds of memory but in quantities of 512MB or less.
3) The box runs slow with other linux distos also. (I tried Redhat 7.2)
Quoted 4 lines
It seems to me that the problem has something to do with the linux kernel and 1GB memory sticks. Am I off base?
Anyone have any ideas?
Maybe, just maybe, you have a PCI-based disk-drive controller and, maybe, just maybe, you are running out of address-space when you install all that RAM, so the disk driver falls-back to PIO?
Try just one, 1GB stick. See if it works okay, then try two, etc.
Cheers,
Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips). The US military has given us many words, FUBAR, SNAFU, now ENRON. Yes, top management were graduates of West Point and Annapolis.
Quoted 3 lines
I have a box running Debian 3.0 with a Via C3 800mhz processor that slows to a crawl when I put in a 1GB stick of PC2100 DDR memory.
What are the specs on the 1 gb stick?
(density, chipcount)