which laptop should I buy out of these three laptops, I'm a beginner in programming, but hoping to advance quickly

[mustafa128h]

I'm a beginner in programming, hope to become an android mobile app developer, can someone tell me which of these laptops would be most suited for me, want something powerful, but portable

http://www.gigarefurb.co.uk/dell-latitude-e6230-intel-core-i5-3rd-generation-2-60ghz-8gb-ddr3-ram-128gb-ssd-windows-7-pro.html
or
http://www.gigarefurb.co.uk/refurbished-laptops/dell-latitude-e7240-intel-core-i5-4300ucm-1-9ghz-8gb-ddr3-ram-128gb-ssd-12-5-hd-windows-10.html
or
http://www.gigarefurb.co.uk/lenovo-thinkpad-t430s-intel-core-i5-3320m-2-6ghz-8gb-ddr3-memory-128gb-ssd-14-windows-10-refurbished-laptops.html

does lower Ghz, means it will be slower, although its a higher generation ?

thanks guys, appreciate your time

 

[mustafa128h]

or if i can afford this should i just buy this, or are the older ones better?

http://www.currys.co.uk/gbuk/computing/laptops/laptops/lenovo-ideapad-510s-14-laptop-red-10146134-pdt.html