Yep...that card doesn't do buffered digital output, and you can't reliably time the output by doing single updates.
What I would suggest is using your 2 analog outputs, if you aren't using them for something else. Your card DOES have buffered digital output. Just multiply your entire arrays by 5. This will give you a 5 volt level for "on", just like your digital lines would have done.
You put your arrays into the analog output buffer, tell the card what rate to output the buffer, and start it.
Mark
