Intel 64bit / AMD 64 bit advantage

ke han ke.han at
Sun Aug 27 10:07:18 UTC 2006

Generally speaking, mail and file server are not RAM intensive.  A 32  
proc can directly address 4GB RAM (2**32).  FreeBSD allows you to  
address more than 4GB on a 32 bit proc but limited to 4GB max per  
process.  The actual per process limit will be a bit less, I think.   
A 64 bit proc can get you 2**64 bits of directly addressable RAM and  
therefore a much higher per process setting.  But if your aren't  
investing in huge amounts of RAM, you are not getting much benefit  
from 64 over 32 bit proc.
Anyway, there is no benefit to running a mail or file server on 64  
bit process ors unless you must have more than 4GB total diectly  
addressable RAM or any single process must get near the 4GB threshold.
32 vs 64 bits does not give you any raw performance boost for most  
apps.  The exception are mathematically intensive apps which would  
benefit from handling very large integers or floats as 64 bits in one  
go instead of breaking down into more than one process cycle to push  
through the same numbers.  A mail or file server does no come close  
to needing this kind of 64 bit math.
A mail and file server is Hard drive and network intensive, NOT RAM  
Spend your money on things like Hardware RAID and redundant power  
supplies, not 64 bit over 32 bits.
have a good day, ke han

On Aug 25, 2006, at 10:56 PM, Martin Miedema wrote:

> I hope that I'm not starting some sort of holy war  with this  
> question, but here I'll go.
> I'm planning to set-up some e-mail / file servers running FreeBSD  
> 6.1 in the near future and I'm wondering if it will be worth the  
> cost to use 64 but CPU's for this.
> Also I would like to know which brand CPU would be best for these  
> applications.
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