[Pc_Support] Memory Technology and Chip Select -- WAS: Rules-of-thumb on upgrading components for an older mainboard ...

[Bryan J. Smith]

On Fri, 2006-09-22 at 22:00 -0500, William A. Mahaffey III wrote:
> Hmmmmm, OK, I wasn't clear on that point. But the net result is (or 
> seems to be) .... a 2 GB limit for DDR400 ?

No, not at all.  There are 2GB and 4GB DIMMs.
And registered DIMMs allow you to use twice as many.

E.g., a single Socket-940 Opteron can actually support 32GiB in 8 DIMM
slots.  A single Socket-939 Athlon 64 can actually support 16GiB in 4
DIMM slots.

> Yeah, same for SGI (& Cray before them), 8 X 32 bit/DIMM for 256 bit bus 
> width on SGI Power-challenges, 32 X 32-bit/DIMM for 1024 bit Cray bus 
> width .... they just called it 'N-way interleaved' (4-way or 8-way for 
> SGI, no name for Cray), not 'N-channel' .... different name, same net 
> result.

Again, that's a mega-over-simplification.  Intel architecture
terminology/assumption is poorly applied to RISC or HyperTransport.

But I'm too tired to even think anymore.


-- 
Bryan J. Smith          Professional, technical annoyance
mailto:b.j.smith at ieee.org    http://thebs413.blogspot.com
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