1S10 dev. board and MAX Freq.

Ya, it helped my NIOS a bit, but hindered the surrounding hardware so I'm back to square one. Thanks to James, I had no idea that the multiplier could be removed (I kinda need it though so maybe it could become a custom instruction). What you said is pretty much what I'm seeing in terms of critical paths. Unfortunately some of the Quartus tweaks are unavailable to me since I'm just using the webpack for now (we got the NIOS II in the mail, but have not renewed yet since I'm finding out if it's worth it or not).

My configuration is some surrounding hardware attached to the custom interface, NIOS II/s, 512B of cache, and I added a hardware divider that I created (I probably re-invented the wheel of the one that comes with the NIOS). I've done a build without my divider to see if that helps and it's not much of a change in fmax at all (probably just resources got moved around and the fmax was affected by that).

When I go with the II/f core and ditch my divider (and just use the one supplied by altera), my fmax goes up around 20%. The results that you were seeing is what I would have expected as well. I'm sure my fmax would have gone up more then 20% but some of my surrounding hardware limits the system to it's own fmax as expected.

So I'll give you're suggestion of removing the multiplier a try (still not sure why it would be used for shift/roll functionality, I guess since it has it built in and doesn't require extra LEs).

Cheers