windows users accessing ical - slow to change from week to week?

Scientific Graphic Photographic Team. Photographers having to give up Macs to access corporate applications.

I was happy that via the PC they could still access existing ical diaries.

by using IE and entering ip address of our Xserve in the URL Bar,

login to the x-serve as the Diary Client, it then takes 20 secs or so to draw the Week's entries (slower than the mac...) but more importantly, clicking to review NEXT week and one has to wait 4.5 mins for a screen refresh....

The calendar dates at top of the page refresh instantly but it's the previous week's entries that remain on display for 4.5 mins before being updated to the appointments that one wishes to review.

Anything I can do at the Mac end to improve PC users' access to the diary?

PCs are corporate PCs with a standard build, locked down, and no additional software will be permitted.