As far as performance goes, the iPhone 5's A6 is only 10% slower than the June 2004-released [1] Pentium 4 540! High end ARM processors (high end for phones at least) should be more powerful than midrange desktop processors from 2003, or 9 years ago. Unless Geekbench changed since then, which I didn't check for. Laptops with Core Duo processors (circa 2006) were indeed faster than the A6 though.

Geekbench numbers for each:

Pentium 4 540 (eyeballed average from [2]: 1800 iPhone 5's A6 [3]: 1623

[1] http://www.intel.com/pressroom/kits/quickrefyr.htm#2004

[2] http://browser.primatelabs.com/geekbench2/search?q=pentium+4...

[3] http://www.macworld.com/article/2010360/lab-tests-iphone-5-l...