Bogdan-G: The Mystcraft profiling was running while you acquired the data, reducing its expressiveness. This may be also the cause for the unusually high memory pressure and lots of client side simulation (mostly entities), which doesn't leave that much time for the actual rendering.
Optifine's smooth world renderer updater wastes some time with reflection, BetterFoliage slows wr updating down, weather2 does nasty edits, the threaded lighting mod is inherently broken and should be removed.
I've fixed the sampler issue for the next (upcoming) version, thanks for reporting it. The issue is sporadic, so it should usually work. The report (srp) format is the most useful for me.