Its a fairly simple equation.
Dual Core processors have 2 full CPU's per chip. Therefore,
they have two sets of cache, and can have two instructions being executed at the
same time.
Hyperthreading is a single CPU per chip that supports two
parallel "trains" of instructions and data into the processor. The only real
benefit to Hyperthreading is that it reduces some of the pain of context
switching within a processor, thereby speeding things up. Regardless of how the
OS presents it (IMO it should NOT reflect as 2 processors), its still only able
to execute a single instruction at a time.
With those ideas in mind, IMO its better to scale AD out
rather than up with regards to performance, depending of course on database
size. I doubt there are a lot of environments where this question is of any real
relevance. Dual core is interesting more from a rack/power density stance than
from its outright speed of processing. In my current environment, we're
seriously limited with data center space in part due to growth of our services,
so we're trying to find more efficient uses of space and power. For instance,
the AMD64 x2 processors[1] draw roughly the same power at full utilization as
their single core bretheren. That's a HUGE savings for power and cooling versus
traditional dual processor machines.
If you do go dual core, I'd also go as far as saying
*which* dual core technology you choose. There's a huge difference between the
architectures from Intel and AMD, both of which have their benefits. However my
personal opinion is that in the vast majority of cases AMD's design is vastly
superior for general computing tasks - the last time I checked, the AMD64
platform uses about half as many clock cycles to go to RAM than the Intel EM64T
design requires. The end result is that for servers tasked with randomized
data retrieval (which AD definitely qualifies as), AMD has
the edge.
It is worth noting however that the Intel EM64T
architecture is better suited for applications where there can be a long,
somewhat predictable, pipeline of data to be processed. For example, I'd expect
things like hard core scientific and statistical processing to be faster on the
EM64Ts.
------------------------------------
Roger D.
Seielstad
E-mail Geek
[1] Which is what my new toy here at home is running - spanking
fast!
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mauricio F. Funes
Sent: Thursday, October 13, 2005 9:56 PM
To: ActiveDir@mail.activedir.org
Subject: [ActiveDir] Domain Controller Consolidation utilizing Dual Core CPUs
Gentleman,
Does
anyone has any information regarding Domain Controller consolidation utilizing
Dual Core CPUs?
I have not seen anything
reports from microsoft indicating the performance boost gained by utilizing Dual
Core technology on DCs. It is presume to be much better that the 20% to 30% gain
from Hyper Threading CPUs.
Thanks for your input,
Mauricio Funes
[EMAIL PROTECTED]
Pasadena, CA
