Everything Apple (the Mac heads thread)

Sorry for the dunce question but what discernible difference will I notice between the following two setups. So far as I'm aware the only difference is that the former has a 2.3GHz Quad-core Intel Core i7 processor and the latter has a 2.6GHz Quad-core Intel Core i7processor.

2.3GHz Quad-core Intel Core i7, Turbo Boost up to 3.3GHz
8GB 1600MHz DDR3 SDRAM - 2x4GB
256GB Solid State Drive
SuperDrive 8x (DVD±R DL/DVD±RW/CD-RW)
MacBook Pro 15-inch Hi-Res Antiglare Widescreen Display
Backlit Keyboard (British) & User's Guide (English)

2.6GHz Quad-core Intel Core i7, Turbo Boost up to 3.6GHz
8GB 1600MHz DDR3 SDRAM - 2x4GB
256GB Solid State Drive
SuperDrive 8x (DVD±R DL/DVD±RW/CD-RW)
MacBook Pro 15-inch Hi-Res Antiglare Widescreen Display
Backlit Keyboard (British) & User's Guide (English)

I've been told to basically get the best up to a limit of about £2,000 and with the min specs of i7 processor, 6GB RAM and 256GB SSD.

I'll mostly be using it for GIS (mainly ArcGIS) and some reasonably intensive spatial statistical analyses for my PhD. This means that Most of the time I'd run it Windows in parallel but switch to bootcamp if things got too clunky.

TLDR: What difference will I notice between a a 2.3GHz Quad-core Intel Core i7 processor and a 2.6GHz Quad-core Intel Core i7processor?