when i bought speaker cables for my klipsch speakers and onkyo amp they look like very long car battery jump start cables as thick as my little finger,one day my windows will pop out.
speaker cables are a lot different,
as large a csa and multi strand as is practical,
up to 200w rms, and 2.5mm csa is more than adequate for home use, multistrand is better, tri-rated is preferrable, shielded even better,
my own el cheapo surround is wired in cheap multi-strand bell wire that I had lying in the shed, lol
its only about 20w [rms], but its never up anywhere close to that, I think I'd blow the little speakers, as well as my eardrums,,,,,,,
btw, most surround manufacturers are very economical about outputs, they simply add everything together and use that, rather than the actual proper output,
EDIT : all this oxygen free shit etc, you are NEVER going to notice any difference at home, and unless you have the means to properly terminate it, then its a complete waste of money.
[ btw, I worked in recording studios, to a spec supplied by others, and heard a lot of home truths by guys that know their stuff, also done rigging for a few years, now, they were BIG audio cables, 240mm+ and the rest, thats about 4-6" diameter per speaker.!!! ]