I've installed Reader 8.1.2 on a 2003 Windows server STD Edition with SP1. Everytime I open a pdf document (regardless of what's contained in it)and I scroll using the mouse or the scroll bar the AcroRd32.exe process spikes near 100% utilization. The effect is, scrolling slows down extremely slow and you loose control of the scrolling until it stops. Once the scrolling stops the CPU utilization comes back down to zero for the AcroRd32.exe process.
Side note, I've tried different types of pdf documents, some with plain text and some with pictures. The same result occurs every time.
I also have this problem. 2 gig ram / athlon 2400+ @ 2.0 GHz. Adobe reader 18.104.22.168
Save yourself the headache and dump adobe. Since they haven't responded i'd give up hope on them. I'm using an alternative open source alternative. sumatra pdf. Initially opening a pdf it's quite slow but after that it's infinitely better than scrolling h311 with adobe's reader.
I'm sorry don't use sumatra use foxit reader it really is faster but scrolling with mouse wheel does use a fair amount of cpu but much better than adobe's reader. If you just opt to click down to the next page level it's seamless and fast.