Maybe you could tell us a little bit more about what it does exactly? What causes the lag, and what does your 'mod' do to fix it?
I will admit that this is probably the laziest post I've written.
What causes the lag:
The nether has a lot of light sources: thousands of lava blocks and many fire blocks. Lighting updates for every chunk is checked per-tick, and that causes extreme lag in the nether. How I try to fix that:
I keep a list of all chunks whose lighting has been checked, and instead of processing the remaining chunks all at once, process them until 4 milliseconds have elapsed and add them to the list of checked chunks. Once this list is full, it is emptied and the cycle begins again.
This also fixes that weird lag you get sometimes when just exploring in the overworld, classified in the profiler under tickChunk.
If you don't believe me that the nether is laggy in vanilla... start up a server, join it, get creative mode and build yourself a nether portal. Once you enter the portal I guarantee your FPS will drop to an almost unplayable level. (That is, unless you have an absolute beast of a computer)
Also if you've ever run a server with more than 10 people playing on average, I guarantee you there will have been many people per week who have asked "why is the nether so laggy?".
Ok, I still don't understand quite well (sorry if I'm missing something obvious here): it's a clientside fix, right? Does this mean it will work when I play on a server? I mean, if this is about screen lag it should work with both modes, right?
Compatible with alot of mods
It fixes the lag in SSP but not SMP. New feature maybe fixing in SMP?
This uses the same solution in both singleplayer and multiplayer, so perhaps there's something else causing lag when you play in multiplayer...? I designed this for my own use and I play mostly multiplayer, so (unless you didn't use the whole mod?) I don't know why it wouldn't work in multiplayer yet work fine in singleplayer. Do you know what section is causing the most lag in the profiler? (After updatechunks, etc, have died down)
Worked for me, though I still get quick lag spikes at some points - I assume when the list is full and is emptied? If so, perhaps that cycle could be altered somehow? (Obviously, I have no clue, as I don't code).
Nonetheless, it's a massive help, and I'm surprised this thread hasn't received that much attention.