Memory/cpu problem with Asus K7M motherboard/Athlon 750

[Mark Steele]

Hi there,

I've setup two servers with almost identical hardware, and identical
software. I've noticed a few problems which I haven't been able to
resolve. (if I'm not sending this to the right mailing list, please let me
know,
I've tried the comp.os.linux.hardware newsgroup, and nobody
has been able to answer my questions).

Server #1: 
AMD Athlon 750
Asus K7M motherboard
512 Megs of 3.3 volt ECC SDRAM
3COM 3c905 ethernet card
Slackware 7
Kernel 2.2.14
Seagate ULTRA WIDE SCSI 2 LVD 9 Gig Cheetah, 80megs/second
glibc 2.1.2
egcs
etc..

Server #2:
AMD Athlon 650
Asus K7M motherboard
512 Megs of 3.3 volt ECC SDRAM
3COM 3c905 ethernet card
Slackware 7
Kernel 2.2.14
Maxtor ATLAS 10k ULTRA WIDE SCSI 40megs/second
glibc 2.1.2
egcs
etc.


As you can see, these are basically identical setup except for the
CPU. First thing to point out, is that both mainboards are using the
same BIOS version. I have also tried to use an updated BIOS
from Asus (release 12/29/99) with the same results.

Server #1 detects 512 megs of ram on bootup (BIOS), but 
linux can only see 64 megs of ram unless I specify mem=512M
in the lilo configuration.

Server #2 detects 512 megs of ram on bootup, and linux
detects all the ram without extra parameters.

Server #1 is incredibly slow. Although it's got a faster processor and
a faster hard disk, it performs horribly compared to Server #2. Here's
an example of timing compilation of kernel 2.2.14 using:
time make bzImage
(after both kernels are configured identically and both servers are
idle with a load of 0.01)
Server #1
real    18m10.465s
user    16m52.590s
sys     1m3.790s
# free
          total       used       free     shared    buffers     cached
Mem   517540     306128     211412      16788     138436     145476
-/+ buffers/cache:      22216     495324
Swap:       265032          0     265032
# cat /proc/cpuinfo
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 6
model           : 2
model name      : AMD Athlon(tm) Processor
stepping        : 1
cpu MHz         : 755.315128
cache size      : 512 KB
fdiv_bug        : no
hlt_bug         : no
sep_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr 6 mce cx8 sep mtrr pge 14
cmov fcmov 17 22 mmx 24 30 3dnow
bogomips        : 752.03

Server #2
real    2m42.281s
user    2m13.650s
sys     0m13.760s
# free
             total       used       free     shared    buffers
cached
Mem:        517488     426344      91144      51512     140992
220848
-/+ buffers/cache:      64504     452984
Swap:       104384          0     104384
# cat /proc/cpuinfo
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 6
model           : 1
model name      : AMD-K7(tm) Processor
stepping        : 2
cpu MHz         : 654.599184
cache size      : 512 KB
fdiv_bug        : no
hlt_bug         : no
sep_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr 6 mce cx8 sep mtrr pge 14
cmov fcmov 22 mmx 30 3dnow
bogomips        : 652.08


Yes folks, the 750 was 16 minutes slower in compiling the kernel.
What's going on here? I haven't been able to figure it out. My guess
is that it's some kind of memory problem, but I'm completely baffled.
Any suggestions on how to fix this would be greatly appreciated.

If you've encountered this problem before and know how to fix it,
please email.

Mark Steele
Systems Adminitrator
Belmont Web Services
msteele en belent.com



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