Dual Core Or Dual CPU - What's the real difference in performance?

[Michael Vince]

Nicole Harrington wrote:

> Hello all,
> I have been building/using servers that were dual CPU
>AMD Opteron systems for some time.  (usually 246
>Opteron cpu's)
>
> Now of course the world is shifting to Dual Core.
>  
> Using FreeBSD, what is really the difference, besides
>power and ability to shove in more memory, between
>having the two seperate CPUS's? 
>
> What if I did 2, Dual Core cpu's? Would the SMP
>overhead and sharing to a [Giant Locked] disk and or
>network erase any benefits?
>
> Thanks!
>
>  Nicole
>  
>
Dual core or Quad Core CPUs performance are far better compared to more 
socket CPUs since they get shared access to memory cache and reduce 
memory latency/probing over AMDs hypertransport bus.
Anandtech did a pretty good review of AMD 4x4 system which compares 2 
AMD dual cores with a single Intel Quad chip, where the Intel chip 
clearly outperforms consistantly because of this fact.
Even when taking Intel out of the equation the benchmarks consistantly 
show even better performance with less sockets for AMD.
http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2879&p=6
There appears to be no advantage to having seperate CPU socket systems 
what so ever.

And yes the power usage is also bad, even though this example is a quad 
setup the fact still carriers over to Dual vs 2 socket CPUs.
http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2879&p=13
Here we have a Quad AMD setup using a whopping 456watts over Intels Quad 
263watt system.
Thats a performance per watt difference of 73% if you even choose to see 
the AMD quad multisocket CPU performance as the same as Intels.

Mike