Re: Single Core2Duo Quadcore vs. two dualcore Xeon?

Johan Strm wrote on Thu, Aug 02, 2007 at 10:41:13PM +0200: 
> Hello
> 
> I'm in the process of purchasing a new server. I'm
currently looking  
> at two Supermicro based options, one with a Core 2 Duo
Q6600 Quadcore  
> 2.4GHz 2x4MB (on a PDSMi+ board) , and another with two
Xeon 5110  
> dualcore 1.6GHz 4MB (on a X7DVL-i board).

Well,  the 2.4 GHz will be faster than the 1.6 Ghz 

I'll assume for the rest of this mail you compare equal
speed
processors. 

> Both configurations would have 4GB (2x2Gb) memory (to
begin with, 4  
> slots on the boards so max 8GB), and I'm thinking about
4x 500GB  
> disks in a raid10 config on a 3Ware 9550SX.
> 
> What my question is, from the performance point of
view, what would  
> be best? Two dualcores or a single quadcore? 

There's two dies inside these Quad chips anyway, and
everything goes
through the same northbridge and memory controller even in
the 2-CPU
soltuion.  The performance difference is almost NIL given
same
clockspeed and same memory speed.

> I'm thinking about  
> memory bandwidth and such... 

The FB-DIMMs are bashed by some for high latency and maybe
that's true
if you use all slots.  Personally I couldn't observe this,
667 MHz
FB-DIMMs perform about as 667 MHz unregistered for me.

However, the 775 platform allows you to either buy 800 MHz
memory, or
even overclock memory, so potentially you get much more
memory
bandwidth if you require it.

On the other hand, the better 5xxx Xeons had 1333 MHz FSB
for longer
and I think the Q6600 is still 1066.  Doesn't do much in
real-world
performance either, though.

> Bus bandwitdh (to ethernet and disks)...

That depends on the busses on the board.  Typically you'll
get PCI-X
on socket 771 boards but very rarely socket 775 boards have
any.

> Looking from the upgrade point of view I guess two
dualcores can be  
> replaced with two quadcores, but on the other hand, if
that will be  
> necessary  then another box is probably a better
solution...

The dual 771 platform also allow much more memory.  I find 8
GB to be
very tight these days.

> Is there any known problems with FreeBSD and these
stuff? From what  
> I've understood Supermicro is pretty FreeBSD-friendly
and should work  
> fine...

Supermicro has nothing to do with any of this, it's all
integrated
into the chipset and some single chips on the board.  But
yes, the
Intel chipsets are as FreeBSD-friendly as it gets.

Martin
-- 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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Martin Cracauer <cracauercons.org>   http://www.cons.org/cra
cauer/
FreeBSD - where you want to go, today.      http://www.freebsd.org/
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On Aug 15, 2007, at 17:38 , Martin Cracauer wrote:

> Johan Strm wrote on Thu, Aug 02, 2007 at 10:41:13PM
+0200:
>> Hello
>>
>> I'm in the process of purchasing a new server. I'm
currently looking
>> at two Supermicro based options, one with a Core 2
Duo Q6600 Quadcore
>> 2.4GHz 2x4MB (on a PDSMi+ board) , and another with
two Xeon 5110
>> dualcore 1.6GHz 4MB (on a X7DVL-i board).
>
> Well,  the 2.4 GHz will be faster than the 1.6 Ghz 

Very true 

>
> The FB-DIMMs are bashed by some for high latency and
maybe that's true
> if you use all slots.  Personally I couldn't observe
this, 667 MHz
> FB-DIMMs perform about as 667 MHz unregistered for me.
>
> However, the 775 platform allows you to either buy 800
MHz memory, or
> even overclock memory, so potentially you get much more
memory
> bandwidth if you require it.

Overclocking a server doesnt seem like a good idea, for
desktop its  
one thing but I'll rather keep my servers stable and secure
than a  
little faster

>
> The dual 771 platform also allow much more memory.  I
find 8 GB to be
> very tight these days.

Yeah, from what I've understood thats the "strong"
thing with FB- 
DIMM... Able to take much more memory..

The Xeon Quad core just got a major price reduction though,
so now  
I'm looking at a dual quad xeon (with 5320, 1.68Ghz or 5330
2.0GHz)  
instead...
The "default" mobo at the supplier (www.mullet.se)
uses the X7DVL-i  
board, which takes 6 FB-DIMMs on two channels (max out at 16
gig)..  
But I'm thinking about getting the upgrade mobo instead,
X7BDE, with  
8 slots on 4 channels with max 32GB (and also full KVM
features in  
the IPMI slot..)

But I'm curious if this kind of platform will ever be able
to use all  
this? Disk access, memory bus & cpu etc.. lets asume I
max this  
system in the future with 32 gigs of mem and 8 2ghz cores..
Will I  
ever be able to use that much with a raid5 (or 10, whats the
lists  
opinion on this? 5 or 10?) config on a PCI-X slot? I think
the disks  
will be the limiting factor before the PCI-X is maxed out
though..  
But realistically, for a php,mysql,apache,java etc machine
with a  
number of jails, i wonder if I will ever be able to use this
much  
power or if I should aim lower and if the box gets too
loaded I'll  
get another one..

Thanks for answers! 

Johan
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