Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I keep hearing all these terms - EN, EP and EX level servers. What do these terms mean? What are they classifications of? How are they demarcated from one another? How are they different from the thin client-thick client server classification used in most literature?

share|improve this question
up vote 2 down vote accepted

It depends on the CPU families;

  • between the 56xx (Nehalem) series CPUs and the Sandy-Bridge Xeons the EP CPUs were designed for two-socket servers, EX CPUs are designed for four-or-more-socket servers. There were also single-socket Xeons sometimes labelled as EP but most were the W range.

  • from Sandy Bridge onwards they're dropping 'EX' and moving to a different naming convention with 'EN' meaning CPUs for one-or-two socket server and 'EP' meaning (confusingly) two-or-four-socket servers.

Four-way 'EP' CPUs can still be used to make >4-socket servers but they need 'glue' chips to manage that, i.e. they can't just do it out of the box.

As for thin/thick-client, there's no direct link - any can CPU can do any role.

share|improve this answer
What about the various phrases such as entry level, enterprise level and data center level servers? Do these classifications relate to the EN, EP and EX classifications in any way? – Arpith Aug 7 '12 at 7:26
This is some loose correlation between these CPUs and phrases, certainly nobody would have classed an EX server as 'entry' but those phrases relate more to the server design than the CPUs. Features such as hot-swappable PSUs/fans/memory/CPUs/adapter-cards, a wide range of sensors and the physical quality of the components used is more likely to define whether a server is 'enterprise' class or not, with the opposite being true - a server without these features is very much an 'entry' one. – Chopper3 Aug 7 '12 at 7:30
Great answer. Helped a lot. Thanks for clarifying. :-) – Arpith Aug 7 '12 at 7:34

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.