Slackware 9.1 + 2GB memory critical performance loss

[gizmo]

Hi all,

I have very bad problems with 2GB memory. I have a webserver
(mainboard is ASUS P400, INTEL P4, IDE discs) and MySQL database, with not so big load.

When I have 1GB of memory activated, it works like charm. However when I activate 2nd GB of RAM, machine suffers terrible performance loss while accessing I/O hard disc functions. THis results into constant load of apache as 99% and unusable system. Unfortunately the web sites requires that much of memory - 1.5GB for standard load (don't ask me why, I only take care about the server. )

What I've tried so far:

1, linux kernel from Slackware 9.1 CD (with compiled High memory ON)
2, vanilla kernel 2.4.25 up to 2.4.27 with both High Memory Support set to 4GB and Highmem I/O support
3, vanilla kernel 2.4.23 with Andrea's buffer bounce patch version aa3 which was supposed to solve the problem. There I set User address space size to 2GB

Memory is definitely OK, I put it on hardware tests and it passed. Also drves are ok.

Please if anyone knows how to help or advice, I'd be glad. I usually don't ask but this is an emergency and I'm stuck with this over two months now.

Thanks a lot

Jan

Ps. the performance loss is not only the apache. eg. kernel compilation is more than 10 times slower with 2GB of memory on.

[pottibaer]

not easy ...

could be a dimm-socket-problem, that first shows itself when you plug in the second RAM -

or

can you try two different (new) DIMMS -

I think, the machine slows so rapidly down cause of the memory-error-handling of the kernel, what would point in the direction that the second memory is not working properly ...

hmm- I bet it is a hardware problem!
... hopefully you can fix the problem

[gizmo]

not easy ...

could be a dimm-socket-problem, that first shows itself when you plug in the second RAM -

or

can you try two different (new) DIMMS -

I think, the machine slows so rapidly down cause of the memory-error-handling of the kernel, what would point in the direction that the second memory is not working properly ...

hmm- I bet it is a hardware problem!
... hopefully you can fix the problem

Hi,

thanks for reply. Unfortunately I tried different DIMMS (brand new) and this behavior is still there. But I already had a thought about bad MAINBOARD although I don't know how to test it.

Jan

[geskorup]

You could try installing another OS and see if it does the same (or not). Yes, it sounds like a DIMM socket issue. I highly doubt you place a brand-new DIMM module in the socket and its bad.. just not right. Anyway, you might try a live-cd like SLAX or something. http://slax.linux-live.org/

George

EDIT: Make sure you dont use ECC RAM on a non-supported mboard.

[gbob1960]

I appear to ave the same issue with Slackware 12.0 and 2.0 GB of ram.

The problem occurs after I plug in the 4th 512 MB memory stick. First three work fine.

The memory sticks appear to be in good working order. It seems to be related to the fourth slot or the OS.