A couple of issues
Ed first of all is it always the STBD tack that slower than Port? It's not uncommon depending on the wind to experience a difference between the two tacks. However it should vary from day to day depending on wind direction, if it's low or high pressure system, etc. This one is probably a long shot but here goes. What do you use to check for wind angle, a masthead fly or an instrument at the helm? After one trip where we had a series of nice long tacks I noticed what I thought was too big a variance in how close I could point and the speeds I was hitting from tack to tack. The difference exceeded 1 knot. The rig is set up properly, the trim was as close to identical as I could get it, but there was still a noticable difference. Turned out to be the wind angle instrument at the helm needed to be recalibrated. What I thought I had for tack angles were not quite real. I was trying to point too high for my boat and of course lost speed in doing so. I recalibrated using the masthead fly as a reference and resolved the problem. I can still have a slight difference based on my first comment but it's generally less than a knot.Good luckMike