[QUOTE=kriesel;583044]Added to [URL]https://www.mersenneforum.org/showpost.php?p=574629&postcount=29[/URL].[/QUOTE]

Thanks. It looks like it is doing the right thing and should be, in theory, little bit (10-15%) faster than v6 stage 2.

I believe you said there was a general FFT regression from v6 to v7. Could this explain why v7 stage 2 is slower than v6, despite having a better stage 2 algorithm?

[QUOTE=axn;583047]I believe you said there was a general FFT regression from v6 to v7.[/QUOTE]It depends on the fft length apparently, per [URL]https://www.mersenneforum.org/showpost.php?p=488535&postcount=2[/URL]

Note due to the time required for even a single PRP benchmark per fft length across all supported lengths per selected Gpuowl version and single OS version, the tabulated values are single measurements each

[quote]Could this explain why v7 stage 2 is slower than v6, despite having a better stage 2 algorithm?[/quote]Partially. It does not explain the full magnitude of discrepancy in V7/v6 P-1 performance ratio, between ~112% expectation and ~75% observation.