A week or so ago, I had posted that Fluent 12 beta seemed to be about twice as slow as the same case running in version 6.3

After doing quite a bit more checking, and looking at the feedback here, we saw (as others had posted) that V12 was actually a bit faster (using Windows serial mode) than V6.3 - for simple cases. X, Y, Z momentum, pressure, and K-eps turbulence.

However, for cases with species transport (finite rate-eddy dissipation) V12 was indeed much slower. Looking at only the species calculations, the multigriding residuals and number of loops were the same in V6.3 and 12. The multigrid setting were identical for both versions as were all of the other solution parameters that we checked.

Fluent support is checking into this but no verdict yet. Anyone have some insight on other things to check?

Is is Fluent support in the UK who are looking into this in the Fluent 12 beta version?

No, just whoever answers the inquiries on the Fluent User Support website. I was hoping that it was just one the default model set-up parameters that needed to be changed or something that might be corrected in the beta version.