Well I've just done a real test.
Yesterday around the same time of day I downloaded a 3.5gig iso file I wanted for installing a new OS on another computer. I thought it was fairly quick as it only took around 50mins. With Opera.
I've just downloaded the same file with Firefox and it was done in approx
8mins.
Now that is some difference. I think I will have to uninstall Opera completely. Including any cache file it may have been using.
This may answer another totally unconnected problem that I have been suffering. I have been writing a program in c++ to gather real time data from a weather station. Every once in a while, totally randomly I would start getting useless garbage for my readings. Now that points to memory corruption, reading un-initialized regions of memory. I will have to wait and see if Opera could be the cause, globbing all the ram.