I'm looking at building a new system to replace an old amd 2500+ machine - I know a 4X Phenom would be stupidly fast in comparison, but would I get a significant performance gain (as well as saving tons of space!!) with a tiny little pc with an atom cpu? (I don't do games, mostly browsing, chat, MS Office).
What are you going to use the pc for and whats the budget?
**Edit, ok, you 'could' have an atom but there are smartphones that will beat its performance
I'd suggest a dualcore running at 3.0Ghz minimum and a Mobo with reasonable onboard graphics, any prefererence as to Intel or Amd?
My feeling is an mATX motherboard, Athlon II x2 260, 4 gb ram, and you have options and upgrade possibilities. An AM3 880 board $60-90, $65 cpu and fan, 4 gb less than $40. Good small cases cost more and are harder to cool.
Intel a Biostar TH67B $80, G620 Pentium $75? equivalent to Athlon 260. This would allow upgrade to any Sandy Bridge in future. I3, I5.I7
The E350 is better than an Atom, but it still isn't great.
I had an Atom R3610 which worked reasonably well. An Atom-based system is fine for general web-browsing, documents and emailing...if you don't mind it being slow. It's not rapid, but it is cheap and cheerful.
I would advise Athlon x2, x3 or x4 if on a tight budget or an i3 2100 or phenom 955 on a higher budget if you want a good performance increase. Also consider the llano A8-XXX series than should be on sale any day if not already. Atom and E350 are really just super low power minimum performance.