Pete, I am using Windows NT (4.0 SP 5) and normally I see a 1 to 2% CPU load. I tested with another PP2 file and saw the same problem. I start PP, load up the PP2 file, and hit resume. The first couple of pings went through fine but as soon as one failed the CPU pegged up. It's not a 100% CPU line but rather was a very jagged 80/100% line.<br><br>One more data element for you. I have an alert on each of my hops that says to log to a file each time one or more traces is over 1000ms. E.g., I log all slow and failed pings. I think the CPU bound condition may be related to my log file.<br><br>I tested again. I loaded up the PP2 and hit resume. This plot has two hops with the second one being down hard right now. I am displaying both time lines. The first ping showed black/red (the first hop is ok and the second fails). The second showed black/red, PP went non-responding, and the CPU did it's 80/90% dance for 125 seconds, after this pings 3 and 4 were displayed at pretty much the same time. After that PP settled back to a normal CPU load.<br><br>If you want I can e-mail you the INI, PP2 and log files.<br><br><br>