[BBLISA] RAM speed difference?

[Dean Anderson]

The difference is 16Gig (4 x 4Gb) vs 4Gig (2 x 2Gb), which could be
pretty substantial--that is, if it matters at all: If your
compute-intensive applictation runs in say 1Gb, but with a lot of loops
(the compute part), then having 16 Gig is a waste. But if your compute
part uses (or could use) a great deal of memory, (eg random access on a
large (16gb+) memory mapped file, then the 16Gig will make a big
difference. But we don't know if this is the case. And
"compute-intensive" doesn't necessarilly mean "memory-hog".  There are
plenty of numerical algorithms that run with a relatively small fixed
amount of memory, but require fast CPU to memory access, because memory
locations are being repeatedly updated or read.  We don't know if this
is the case.

The correct choice depends on things we don't know, yet.

		--Dean

On Sat, 22 Dec 2007, Scott Ehrlich wrote:

> I'm pricing out some servers (from Dell) and deciding between their 1955 blade 
> server and a 2950 2U server.   I learned the 1955 has only 4 RAM slots, whereas 
> the 2950 has 8.  Thus, I could populate with 4 x 4 GB modules, or 2 x 2 GB 
> modules (cost savings).  But, for compute-intensive work, where the majority of 
> a program will work between CPU and RAM, how much of a cost, compute-wise, is 
> there, between 4 GB and 2 x 2 GB?
> 
> I could go with 10 blades, or 10 2950 machines.   The benefit of the 2950 would 
> be more slots for RAM and, with its architecture, easier to manage and expand 
> (I work with two of the 2950 machines anyway, and have seen the 1955).
> 
> I'm not a/the programmer.  I'm just relaying, and using my resources to get the 
> best hardware that fits the need.
> 
> Thanks for insight/feedback.
> 
> Scott
> 
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