The only reason to wait for a 48x is so the 40x will drop $3 in price. You will see almost no difference because of lead in, lead out times and such. Don't bother.

I have a 52X write speed Samsung SM-352B and I ordered my second batch of 100 count Taiyo Yuden CDRs. When I burn with Nero (5.5 10.5 bundled) the first thing it tells me is that it can only burn at ...