You are not alone. PPRuNe's speed has been up and down a lot recently. It got very bad just after the WTC attacks and then it was a little better.
Now, however, it is unbearably slow and like you there are times when I have given up.
For instance, the elapsed time between my clicking on the button "Reply to Message" and the "Post a Reply" screen appearing was over 50 seconds.
In fairness, my Barclays Bank Access has been even slower during the day; at times it is 3-4 minutes between changing screens. I've given up on them to wait to a later time in the evening and it is ususally better. PPRuNe does not improve in the evenings because there are so many more people browsing the site.
Other Sites are fine with times of 3-4 seconds to change screens.
I'm on ISDN at 64 kBits/sec, 500 mHz Pentium 3 and 256 mB of RAM.
Very frustrating at times.