First, the first line of output of "vmstat" should always be ignored, as i said. Because you only have shown one line you should not use this output at all to base any assumption on it. IIRC it displays an average since last reboot or so, which is meaningless.

Second, the system is next to idle. Between 3.1% and 0% there is not much difference and the "load" could well change that much within one or two seconds (the time you needed to stop one and start the other process).

Third, both tools, "topas" and "vmstat" use a certain sampling interval, which is probably not the same per default. I use "topas" only rarely, so i could be wrong, but i believe the default sampling rate to be 2 sec. With "vmstat" there is no default, you have to provide a sampling rate (in secs). I usually start with 1 sec (my internal clock is counting that way) for intensive monitoring and (up to) 60 seconds for long-term observation.

Both, "topas" and "vmstat" get their data from the same OS interfaces, but because they treat these data differently they might end up displaying different values. I have never attempted to search for it, but i am sure you could find the OS calls both are using documented somewhere and you could write your own monitoring tool if you are determined enough. I always found that "vmstat" is giving me the data i need and in a form i can easily manipulate with the abundant UNIX text filters there are (grep, awk, sed, ksh, ....). This is why i myself use "vmstat" and hardly ever "topas": personal preference rather than technical reasons.

I hope this clears it up.

bakunin