The two processors Seem to be:
http://ark.intel.com/Product.aspx?id=50067
http://ark.intel.com/Product.aspx?id=52219
and the differences are more than just clock speed - the faster one also has faster memory bandwidth, along with plain old 'more features' such as VT-d Virtualization for directed IO, Execute disable, Quicksync video, wireless display, mywifi, 4G wimax... but what it means for those things to have built in support in the CPU, I don't know.
I'd predict that the memory bandwidth, which is about 20% higher in the faster chip, would have more of an observable effect than the 10% faster CPU, but that unless you have an intensive use planned the difference wont be worth much worrying about.
Far better to look at an SSD instead of a normal hard disk, that will provide a big shift in the feel of how responsive everything is - the hard disk is the biggest bottleneck in normal computers these days. (Where a hard disk can shift 20-40Mb/s sustained, an SSD can shift 100-200Mb/s sustained. Where a hard disk can handle 100 operations per second, an SSD can handle many hundreds or a few thousands).
For which types of applications will the different graphics cards have an observable effect in performance?
- Graphics heavy games, racing and running around shooting, flying and the like (not cards, dice, board, web/flash games, etc).
- Graphics heavy apps like architecture modelling, 3D scene rendering, Pixar style film rendering.
- Currently niche apps which make use of the graphics card as a spare processor - at the moment this means things like distributed computing project SETI@Home, and PowerDirector 7 video encoding software. However, there is a push in the industry to make this more widespread, but that's probably still too far away from every day uses to bother about for another year or three.
My vote is that unless you have a particular intensive workkload or unusual use which you haven't mentioned, the 2.0Ghz will be fine, and if you can spare the money then see if you can find a machine with a good SSD to compare, and consider one as an upgrade, for an everyday snappiness boost. (Apple supplied, or aftermarket).
I have this kind of setup in my Mac mini, 120 Gb SSD, 320 Gb HDD. Instead of doing mounts or messing with the location of the home folder I decided to just link the "heavy folders" back to their location on the HDD :
$ ls -l
total 1304
drwxr-xr-x 17 tyr admin 578 Apr 17 01:51 Applications
drwx------+ 6 tyr staff 204 Apr 21 20:20 Desktop
lrwxr-xr-x 1 root staff 35 Dec 31 08:15 Documents -> /Volumes/MiniHD/Users/tyr/Documents
lrwxr-xr-x 1 root staff 35 Dec 31 08:19 Downloads -> /Volumes/MiniHD/Users/tyr/Downloads
lrwxr-xr-x 1 root staff 33 Mar 18 16:11 Dropbox -> /Volumes/MiniHD/Users/tyr/Dropbox
drwx------@ 56 tyr staff 1904 Apr 18 03:49 Library
lrwxr-xr-x 1 root staff 32 Dec 31 08:19 Movies -> /Volumes/MiniHD/Users/tyr/Movies
drwx------+ 6 tyr staff 204 Feb 19 04:35 Music
drwx------+ 25 tyr staff 850 Apr 21 16:24 Pictures
drwxr-xr-x+ 88 tyr staff 2992 Apr 8 11:17 Public
drwxr-xr-x+ 3 tyr staff 102 Dec 31 08:02 Sites
lrwxr-xr-x 1 root staff 41 Dec 31 08:30 VirtualMachines -> /Volumes/MiniHD/Users/tyr/VirtualMachines
drwxr-xr-x@ 2 tyr staff 68 Jan 11 19:51 dwhelper
drwxr-xr-x 2 tyr staff 68 Dec 31 08:54 lf5
I've had this setup for a couple of months now and have not had any problems with it.
2 folders are not linked : "Music" and "Pictures" because I've changed the location of the music and pictures in iTunes and iPhoto respectively. For iTunes this allows me to keep the metadata (the iTunes "db") on the SSD where it is fastest.
Best Answer
Usually when Apple says "SSD" they refer to a removable/upgradeable solid-state (flash) storage device. The MBP with Retina Display (and the MacBook Airs) are also using solid-state storage, but they are non-removable.
See also: http://www.pcmag.com/article2/0,2817,2371288,00.asp