155 reputation
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location Gothenburg, Sweden
age 36
visits member for 2 years, 1 month
seen Oct 21 at 6:00

Founder of RoboVM (@robovm). Co-founder of Trillian AB and SpamDrain (@spamdrain).


Sep
24
awarded  Autobiographer
Apr
20
awarded  Notable Question
Feb
26
awarded  Popular Question
Jan
24
awarded  Teacher
Sep
27
comment AMD 24 core server memory bandwidth
Well, your're probably right. But the nerd in me just can't let this be! :-) If you're not already tired of me please help me explain this: They have now added back the 4GB modules that were taken out before making it 40GB in total again and 5-5. stream again gives poor results. But I just tried to remove the numa=off boot option and after a reboot stream gives me close to the excellent results I saw with 32GB in my last update.
Sep
27
accepted AMD 24 core server memory bandwidth
Sep
27
comment AMD 24 core server memory bandwidth
Ok, that's what I feared. I don't understand why they let me buy 40 GB if that's not going to work optimally. :-( Thanks for all help!
Sep
27
comment AMD 24 core server memory bandwidth
@chx - it seems like you're were right with the single channel mode. Please see my last update.
Sep
27
revised AMD 24 core server memory bandwidth
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Sep
26
revised AMD 24 core server memory bandwidth
added 440 characters in body
Sep
26
comment AMD 24 core server memory bandwidth
The hosting company which I rent it from has changed the layout of the modules to slots 1-4-7-10-3 which is what HP says in the manual. No noticeable difference though in my tests. I have now asked them to remove that last 4GB module on each side.
Sep
25
comment AMD 24 core server memory bandwidth
@ChrisS: I've updated the question with more info on the memory modules and the current layout.
Sep
25
revised AMD 24 core server memory bandwidth
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Sep
25
revised AMD 24 core server memory bandwidth
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Sep
25
comment AMD 24 core server memory bandwidth
The RAM modules in the AMD server are ECC modules. I don't know about the Intel server. dmidecode doesn't give any info on the modules it uses. But could ECC really explain the huge difference? Googling suggests that ECC RAM gives a few % penalty. I'm seeing a lot more than that here!
Sep
25
asked AMD 24 core server memory bandwidth
Sep
25
awarded  Editor
Sep
25
revised HP P410 RAID + Samsung 830 SSDs + Debian 6.0 - What performance to expect?
added 653 characters in body
Sep
25
answered Linux - real-world hardware RAID controller tuning (scsi and cciss)
Sep
25
comment HP P410 RAID + Samsung 830 SSDs + Debian 6.0 - What performance to expect?
I'm playing with nr_requests and read_ahead_kb. I've also found that with iozone instead of dd I get quite different numbers and the differences between the servers seem to vanish.