I assume you have 25 desktops and now you want a server to provide managed services for these desktop, very well!
Well first, choosing the right processor and RAM - Remember that be it microprocessor, RAM, HDD, motherboard, all these major components are chosen on some basis depending upon what exactly you're trying to achieve just like the rest of the components of your system. For instance, I would never suggest you to go for a 7000 series processor with lots of RAM in case you are setting up a server that does not require much compute intense applications/services to be hosted on it when you can live with a low end server processor and sufficient memory.
Secondly, configuring a server according to your needs ... here is a URL you might find useful:
Additionally, you can choose a processor and/or motherboard that suits your needs.
With PROCESSOR FINDER TOOL, you can choose a server processor (Itanium/Xeon) and further select the options you want a processor to be capable of, e.g. Virtualization, Demand Based Switching, 64-bit capability, etc etc.
Further, to find a suitable motherboard, you can either look up the compatibility list for the selected processor or individually select a SERVER MOTHERBOARD that fits your needs or find one that suits your requirements.
To do a compatibility check, though you have the compatibility list available for each processor/motherboard but still PROCESSOR MOTHERBOARD COMPATIBILITY TOOL is a plus.
Now, Amit ... to configure a server according to your need, you first have to provide us the details of the following if you want us to help you otherwise following the steps above, you can always configure one according to your needs:
Services you are planning to host on that server.
Network bandwidth considerations.
Hard drive capacity.
So you see, these are just a few of those considerations you need to keep in mind when configuring a server.
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