It wouldn't surprise me if it's quicker but what I was wondering was how this Mini 10 CPU will fare against the 640m's speed wise?
The most demanding thing I'll be using this for will be simple Photoshop work so I can update my travel blog / emails, maybe some pano's and RAW image processing. Plus control my camera for time-lapse.
Would it be fair to say that the Mini 10 could be slower?
Not just slower, quite a bit slower.
Even one of the long battery life CPUs like the Intel SU4100 @ 1.30GHz gets a Passmark CPU score of 988 (Dell Inspiron 1110 $449).
The dual core Atom 330 get a 632. Updated dual core Atoms are thought to be on the way shortly. Single core Intel Celeron 743s get 487 (as in the base $370 12" 2GB RAM Inspiron 1110 1366x768).
Netbooks are fine for email, text editing (blogs, etc) and web surfing. They're not so bad watching DVDs and videos although you can get stutters and dropouts with HD flash video content. Multi-tasking? Starts to get dicey on a netbook. And the small 1024x600 screen can make you crazy trying to get any actual 'work' done. 1280 x 800 doesnt sound much bigger but when you consider room for the menus and toolbars, etc it can see like 50% more usable workspace.
You can get a 10" & 12" 1366x768 Netbooks but that pushes the price near $400.
Here is a Dell 11z review It should be close enough to the 1110's to give you a good idea what it's like.
And because you can never have too much information.... here's the Dell mini 10 review.