Hm.
I hadn't played with thaumcraft in a long time, so I decided to do a magic/tech world.
But boy is gregtech killing my fps for some reason..
I set up a fresh profile, added IC2/GT6/TC4 & fastcraft. Turned off sound, disabled vsync and set fps to max/unlimited.
Created a superflat redstone-ready world, hit F3 and waited for the world to settle down (memory alloc rising by dozens of MB/s rather than hundreds of megs).
Standing still I get ~600 fps with or without GT. Not a problem.
Scanning sandstone and then watching it through the thaumometer I get ~500 fps w/o GT and ~55 fps (!) w/ GT (and memory alloc is rising by the hundreds again).
That's below my refresh rate.. And if I hold down the right mouse button (to try to scan the already scanned block) it further drops to a slide-show at ~24 fps. That's old movie-era framerates, and does not happen w/o GT.
Now I know GT can be a bit heavy, but I still feel like something is seriously wrong here..
Is anyone able to replicate my findings?