Task manager...
8-Core-Taskin.gif

I have never tried quad core, but with dual core and pre-SP1 install it doesn't see dual core until you apply updates. As a matter of fact you get an error during install regarding multiple processors, which you can ignore. If it's a new R2 install it will be seamless.

As others have suggested, you shouldn't have a problem... though I think you're going WAY beyond what you need for that server.  No way I START with 2 quad cores... A single dual core should be fine... but if you wanted, then a single quad core.  I'd save the money and invest in a faster disk subsystem.

Dual Quad Cores on an SBS box is a little like taking a Winnebago to the grocery store.  It works... but it's WAAAAAY overkill.

to answer your question, SBS 2003 has a limit of two physical processors.  They can be multi cored without a problem.  

I am running a dual quad core Dell with 4GB of ram and it runs great.  The notes you read on the website are inaccurate.

be careful if you going to run SBS premium, as the ISA server will fail to start (but it will install ok) if the server has more than one multicore processer, as it thinks there is more than one actual processor.

This is fixed by installing the latest ISA service pack (SP3 i think at the moment)

leew,
You know 8 cores does seem to be an overkill but for the PE 2900 III there is not much choice of dual core CPUs, it's mostly quad core.  I do want two physical CPUs. So I tried PE 1900 that offers better  dual core CPU selection but the cost is just about the same as for the 2900 which is newer model and offers power supply redundancy.

As for the disk subsystem, i am going with SAS 6/i controller and SAS HDs. I could go with PERC 6/i but looks like then you must have RAID. I don't want RAID. Can i have PERC and not have RAID?  Which one is better PERC or SAS?

Thanks.

Thank you all for your help.

Why would you not want RAID?  That doesn't make any sense... a server should ALWAYS have RAID, ESPECIALLY an SBS server... not having it is foolish.  And two processors doesn't make any sense when you have one with 4 cores.  You want Power Supply redundancy but don't want disk redundancy?