I did internet speed test after wondering if aluminium bumper will affect the internet speed... i'm using same wifi connection and same server for this test... not much different but without aluminium bumper the connection seems more stable and never reached below 10mbps for download speed...
With Aluminium Bumper :1st attempt : Download 10.88mbps / Upload 13.10mbps
2nd attempt : Download 9.11mbps / Upload 13.24mbps
3rd attempt : Download 10.89mbps / Upload 13.40mbps
4th attempt : Download 13.43mbps / Upload 20.23mbps
5th attempt : Download 10.52mbps / Upload 16.59mbps
6th attempt : Download 9.99mbps / Upload 21.06mbps
Without Aluminium Bumper :1st attempt : Download 14.79mbps / Upload 23.61mbps
2nd attempt : Download 14.58mbps / Upload 18.46mbps
3rd attempt : Download 11.65mbps / Upload 21.89mbps
4th attempt : Download 15.20mbps / Upload 17.92mbps
5th attempt : Download 10.25mbps / Upload 13.84mbps
6th attempt : Download 13.18mbps / Upload 16.27mbps
I've read somewhere the main reason apple i 4 & Asus Prime got problems with reception & wifi reception is because the effects of its antenna against the metal built of the machine... N aluminium is a type of metal...
That is why Samsung used almost all plastic design on for their latest smartphones..
. Ive also tested the same thing with my S2 previously. ..without the aluminum bumper the wifi & telco reception is much2 better! XD