Machinery is irrelevent. Any mod that adds any recipes will contribute to load lag and GT related load times, no matter how simple or complex. It's simply about quantity. So a mod that adds a ton of recipes, regardless of if they're simple or even vanilla-like, it still going to make Forge's sequential load method take ages, and as we've established, GT scans the Forge recipe database on load. Thus, you have the problem- too much stuff.
Also, you've named a LOT of the kind of mods responsible for this. That is a HELL of a lot of recipes you have added in there, several times more than MC has vanilla. More than GT adds, even, by a large margin. So what we're looking at is your modpack has more recipes than 'normal' by a factor of ten or more.
Forgot to say : I usually have 60 fps playing in short + 32 (optifine setting) using BOP, whereas playing with GT, IC2, Mekanism and Forestry makes me drop to 30 fps in tiny, without BOP.