I tried Prime 0, A, B, 1, 2, 3, 4, 5, 6...current and found none were worth my time to convert everything from M15 when M15 works for what I need to do and it required major conversion efforts. I have to admit, I skippeed a few releases becasue there is only 24 our sin a day. Plus, with a permanemt license I am not paying for their development.
For dimensional and mechanical properties I use external Mathcad worksheets, used for all my structural calc seets.
In many cases, I use subscripted variables to choose options.
I also use many If then if then if constructs that look like this:
I don't write to go faster but sometimes I disable automatic recalculate when I'm developing or making major changes.
I use "areas" and collapse them when not needed, but I think they still calc
As a test, I closed all instances of Mathcad and double clicked on a tank worksheet.
It took 10 seconds to load Mathcad, open the file and give me a cursor
I'd be happy to review (in total confidence) your file if you want.
If it works sometimes and not others that might point yoou somewhere - does Prime increase its memory footprint over time?