[Tfug] Processing/memory throughput and suggestions

[Jesse Allen]

John Gruenenfelder wrote:
> I've found a Gigabyte motherboard (GA-E7AUM-DS2H) that takes a quad-core Intel
> CPU and up to 16GB of DDR2-800 memory.  I'd put into that an Intel Q9550S
> 2.83GHz quad-core CPU with 12MB cache.
> 
> But, it occurs to me that I might possibly achieve better throughput if I went
> with a true dual-processor motherboard and put onto it two dual-core CPUs.
> More paths to the memory means less contention inside the CPUs, but, of
> course, there can still only be one thing accessing memory at a time.

The quad-core is going to be faster. The fact that at least L3 cache is 
shared makes a tremendous difference. Remember that every time the CPU 
has a cache miss, there is a huge delay. The difference between an L2 
cache miss and a cache miss which requires going off-chip is 
astronomical. When I say astronomical, I'm talking orders of magnitude 
difference. Having dual CPUs compared to a single CPU of comparable 
processing power is like working in North Phoenix and living in South 
Tucson compared to living and working in the same town.

Hope that helps. It's too early to go looking through my computer 
architecture texts, so I'm sorry I didn't provide any real numbers.

- Jesse Allen

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Stay away from flying saucers today.
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                                Jesse Allen
                               jessecarl.com
                               (520)850-7298
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