Thanks Bobster. I got 128x Sphax working in GregTech, but wow did my load time increase. I used to be playing within one minute from launch, but with 128x Sphax it took about 4 minutes and I allocated 8 gigs of RAM so it doesn't stutter (I have 32 gigs total). 8 GB might be excessive, and of course there's always that warning from AT Launcher that you should never allocate more that 4 gigs (which I disregard and believe to be incorrect advice). I've run Sphax on 7 gigs before but that was as low as I could go. Any less RAM and it would stutter horribly.
It sure is great to be back in Sphax cartoon-land!!!
Edit: I guess I jumped the gun. When I go downstairs to where my GregTech Electric Blast Furnace and Bronze Steam Boiler multiblocks are, my game bogs down and stutters too much. Might have to drop down to 64x after all except... I don't see anything except 128x for GT.
I found the ultimate problem - when AT Launcher gives that warning about allocating more than 4 gigs of RAM, it isn't a suggestion. I appears to actually reset the RAM setting to 4096. That's complete BS but since this is FTB and not AT I guess I won't say anything more about it here. Who can possibly run a GregTech modpack and a 128x resource pack on 4 gigs? Nobody.
Sound to me like you're slightly deficient in your RAM allocation? Perhaps bump it up by 1 GB if you can afford to (I think suggestion is to leave 2 GB for windows to use, if you're on a windows rig of course).