Known Issues
Optifine - Use Ultra B5
Fastcraft - Doesn't work for everyone, you have to test it on your own.
Improving Performance
Per-Generate your world by entering the command /pregenspawn [50-100]. This generates a whole bunch of chunks in advance and can prevent major lags while exploring early on. Keep in mind that this process takes some time and you have to re-enter the world after the process has finished, after that you should have a much smoother expirience.
Hide unwanted blocks/items via the NEI Subsets, for example Forge Microblocks, not only does this cut down on the NEI pages, it will also safe some memory in your client since those blocks/items don't have to be loaded any more. At least until you craft them.
Optifine - Use Ultra B5
Fastcraft - Doesn't work for everyone, you have to test it on your own.
Improving Performance
Per-Generate your world by entering the command /pregenspawn [50-100]. This generates a whole bunch of chunks in advance and can prevent major lags while exploring early on. Keep in mind that this process takes some time and you have to re-enter the world after the process has finished, after that you should have a much smoother expirience.
Hide unwanted blocks/items via the NEI Subsets, for example Forge Microblocks, not only does this cut down on the NEI pages, it will also safe some memory in your client since those blocks/items don't have to be loaded any more. At least until you craft them.