Wow, that's slow. Your example showed me (at first run) 435ms, in consecutive runs around 220ms. jNizm's seems as fast (almost instantly), the sample script the same.
So I guess, there is something going really wrong on your system. I tested with a refurbished pc (at least 5 years old) and Windows 7 (64bit Home Premium) and AHK 1.1.26 Unicode 64bit - most probably not the fastest computer out there
Are you using some Antivirus prog like AVAST (which is notorious for intervening with AHK)? Not sure, but there might be some benchmark scripts already around for AHK - are you experiencing such delays or other strange problems also with other AHK scripts or totally different programs?
But anyway, your times are so much off... Still, I am going to test it on some older and much slower machines - but I guess that they won't be anything slow like yours... hopefully someone else will chime in with some possible insight.
Edit: On one laptop with Win10 32bit (around ten years old), your script clocks in around 500ms (first run) and 330ms in following runs...