Hi,

I am trying to compare the performance of different servers for use as
a web server.

DELL poweredge 8450
- 8 x Xeon 700Mhz Processors installed (700/100/2M Step - SL4XX) 
- 2048Mb ECC SDRam 
- 2 x 36Gb Hot Swap HDD (15k) 
- RAID - Perc 3/Dc 128Mb Controller 
- 3 x Hot-Plug Power Supplies 

This is a 2nd hand machine purchased off ebay

DellTM PowerEdgeTM  2850
Dual-Core 2.80GHz, 2x2MB L2 cache, 800MHz FSB

This is a new machine from Dell, both would be running Linux and whm/cpanel.

Would there be a big difference in performace between the 2?

The load is likely to be 2,000 plus small websites.

Adrian

Adrian,
It's hard to find benchmarks for both of these machines, since they
differ so greatly in age.  However, I think that this might be of
help.

The Dell PowerEdge 8450 (with 8x 700MHz processors) has a published
web performance of 8001 using the SPECWeb99 benchmark, and while Dell
never published a SPECWeb99 benchmark for the Poweredge 2850, the
Poweredge 2650 gathered a score of 5698 with 3GHz processors.  Since
you are running 2.8GHz processors in yours, it is not an even
comparison, but I feel that the architectural differences between the
2650 and 2850 will even out that difference.

One of the other things to take into consideration is that with the
dual-core design of the 2850, you will be "nearly" doubling the
processor performance of the 2650.

I would feel confident in stating that the 2850 running on Linux with
a 2.6 kernel and a modern version of Apache would nearly double the
performance of the   8450.


Sincerely,
Kent Rankin

kentrankin-ga has given you an excellent answer.  Other points to
consider are what other things can bottleneck the system.  Do you have
enough bandwidth to handle the load?  You could have the fastest web
server in the world, but if the pipe to it is small it won't matter. 
ALso how much IO is going on?  If you need to get more data off a hard
drive faster than it can be delivered the CPU won't matter.

Performance is a chain and the slowest link will determine the
performance.  Keep that in mind.