I have no experience in specific CASA slowness, but I agree with Alastair (I think).
The best time for me to access CASA (wrt speed of connection) is between 5pm (my local time) and about 8 pm. After that, and before that, it is far slower. So, given that the Western Hemisphere is 5-6 hours (behind, I think? - you are awake and we are still asleep), i.e. at 10 AM GMT, it's 5 AM, my time (right?). So at 5 PM (my time), it's noon GMT (yes, I know that is the old way of saying so, but I can't remember the new "translation".)
I may be adding and subtracting incorrectly. I figure these things are designed SPECIFICALLY to disturb me (joke). I can't get on a plane whose destination is a one-hour difference and figure it out. You folks will set me straight, I know. But a 1-hour difference does not distort one's sleep patterns.
I went to Europe and had to sleep - immediately (depite being told not to). I came back to Canada, and I was rarin' to go. Flights going east are late afternoons flights. Flights going west, at least from Europe (I believe), are morning flights. Not withstanding that they fly at different altitudes (so they won't crash). Congestion in the air? Probably Europeans travelling here may have the opposite experience, though it may depend on how long one has been awake. Does "jet lag" work the other way, or do you Europeans not experience this phenomonon? Or only on return? We have jeg lag going east, while none coming back. Though it may have something to to with the "experience" while you are on holiday.
I suppose it depends (in your time zones - in the Eastern Hemisphere) where your Internet periods of high usage are. And where the receiving parties overlap. There are those who access at work, and those who access at home.
As far as I know, (in my "small" part of the world within this time zone) we have 6 time zones, I believe in Canada, and this does make a difference. The last I read, most access was during work hours, but that may have changed.
I know I am equating air travel with Internet usage. But there may be a relation between the two.
Can you try connecting at your time zone to other sites within that/another time zone and see what happens? Try also connecting to those "really" far away like Dorothy's site from Australia?
And do the math. And tell me if I am "forward" or "backward" . I really should not get involved in this discussion, since the only "fact" I can reference is that the sun rises in the east, so you are "earlier".
See, aren't you glad you asked?