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Memory amount vs. memory speed?

idata
Employee
1,744 Views

Could not find the answer for the question:

How is memory access organised in Nehalem 5500/5600 series.

Well, the documentation says that the processors have 3 memory channels, each supporting up to 3 memory slot, with up 8-rank memory modules (with up to 48 ranks in total).

Also you have 1333MHz memory speed with up to 8 total ranks, 1066MHz with up to 24 total ranks, 800MHz with more and max 1066MHz with 8GB / 800MHz with 16GB modules

And that is tho whole info I could find. But this is not adequate!

Sample question - now there are 2GB 4-ranks modules and 4 rank 16GB modules - will both run at 800MHz if 12 modules are intalled?

Really I'd like to get the answer for the following - which way the memory is adressed and reached.

Is it spanned across banks/ranks (bank1 rank1 - bank2 rank1 - bank3 rank1 - bank1 rank2 - bank2 rank2 ...) or some other way?

When it is possible to read/write the next rank of the bank (after 7-9 clocks or after 20-22 clocks or more)?

I want to understand the dependance of the amount of the memory installed on the real memory speed.

In workstation applications the big RAM-drive is a great help, but if it decreases system number-crunching performance, may be it ai more wise to have it on an axialary server?

2 Replies
idata
Employee
353 Views

Hello,

Check this link

/community/openportit/server/blog/2009/05/05/nehalem-memory-help-im-lost [+++]

Any further question, may be you can ask the author of the blog.

All the best,

Kind Regards,

Aryan.

/poll.jspa?poll=1129 Voting Poll

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idata
Employee
354 Views

Thanks, but that's just the same info as in Intel documentation.

Should say that memory usage for 7500 Xeons is described much better.

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