I have had similar experiences on machines, and have seen three things that have caused that type of effect:

• the most common case was a huge number of 0 length files in the cache folders; hence, as soon as 4 or 5 programs opened, there were longer and longer delays as the cache folder filenames were processed; (this, of course, is also a function of drive speed/age)
• a keyboard with a flaky ctrl key, that kept intermittently triggering; (that one was picked up when 4 computers all of a sudden started experiencing the same delays on a 4-port kvm)
• a flaky usb port or mouse - always intermittent

I have also noticed that effect more frequently if IE is opened with a few windows, (lag time increases with the number of IE panes opened), and some of those hyper-irritating video ads start silently downloading in the background - easy to check - if it happens, hit the ESC key on each of the IE panes, or pause any videos. Hope this helps!

I have had similar experiences on machines, and have seen three things that have caused that type of effect:

• The most common case was a huge number of 0 length files in the cache folders; hence, as soon as 4 or 5 programs opened, there were longer and longer delays as the cache folder filenames were processed; (this, of course, is also a function of drive speed/age).
• A keyboard with a flaky ctrl key, that kept intermittently triggering; (that one was picked up when 4 computers all of a sudden started experiencing the same delays on a 4-port KVM).
• A flaky USB port or mouse - always intermittent.

I have also noticed that effect more frequently if Internet Explorer is opened with a few windows, (lag time increases with the number of Internet Explorer panes opened), and some of those hyper-irritating video ads start silently downloading in the background (easy to check) if it happens, hit the esc key on each of the Internet Explorer panes, or pause any videos.