Bert,
Here's an article from PG Music on latency.
http://www.pgmusic.com/tutorial_bbwlatency.htmI remember that a few years ago, when I installed BIAB on a brand new computer, the latency factor increased considerably even though I had had very little latency only the day before on the previous computer.
Then something happened. I went back to my computer the following day and the (lack of) latency was back to what it had been on my old computer.
I have no idea what I did but it seems that I must have entered into something and simply by entering that and then exiting it, I had changed something.
I mention the above because even though I have no idea what happened, there are some things to try. Below is the process that I would have gone through so it might have been what solved the problem.
Let's try this ...
Actually, before trying anything, save your present settings by using "Opt | Save preferences as ..." - this then gives a way to get back to your present settings if the below attempt is fruitless.
1. Click on "Prefs" (#1).
2. Now select "Midi Driver" (#2).

In the Window that pops up (as shown above) ...
3. Click on "Get Input Drivers" (#3) and then select the input that your keyboard is attached to (#4).
4. Click on "Run Driver Wizard" (#5) and choose the top option for the GS Wavetable Synth. Click OK. Check that the Wavetable synth is selected (#6).
5. Make sure the two check boxes for "Use VST/DXi Synth" and "Route MIDI through MIDI driver" are un-checked (#7).
6. Set #8 to 120 (as per the instructions below this window).
Exit the setup. Close BIAB. Restart the computer. Restart BIAB and try it out.
It might not be a solution but it's worth a shot.
Hope this helps,
Noel