Use a demo of a third party charting package fed by the IB api such as www.multicharts.com www.linnsoft.com www.medvedtrader.com www.serrachart.com www.ninjatrader.com www.motivewave.com to see if you get a delay via the api. Maybe it is just IB TWS mosaic charts.
Thanks for the tips. I'll check with IB support first.