Hi, I can reproduce your problem with my ppc and your VI.
I believe the lag we see is not introduced by the daq board (I created a channel in "on demand" timing mode and the problem still arise) but by the pda that is not fast enough to keep up with display update. (I believe those update callbacks are deferred...)
Examples that come with the nidaqmx base behave differently, they use a graph instead of a chart and each update show actual signal.
I obtained better results also with a chart fetching 10 or 20 points instead of 1, in this way your application refreshes indicators only one time each 20 samples.
Also consider that buffering your channels ("continuous" timing mode) helps you to obtain evenly sampled data and to be less dependent from PDA jitter, PPC is not a RT os, so it does not assure you to achieve a task in a specified and precise time. Visualization of your buffered samples could be delayed by lack of resources, but the data you obtain would be somehow time stamped and you can keep track of when something happened.
Hope this help.