My wind mills are kinda loud, i have 32 linked.
when im near them my fps is good.
when i get away, my fps drop alot.
Turning sound off, stops the huge fps drop.
Please can someone explain WHY this happens?
This may be in the wrong section, if it is move it please.
I have the same issue. Replacing the .ogg file with silence does not change it. My machine should be more than adequate for this game (Phenom 9950, 8 GB RAM, X-Fi Sound Card).
I'd prefer not to have to play in silence! 
You can turn off the IC2 sound in the IC2 config file. That is what I had to do in the end. I do miss the IC2 sounds but it is better than not being able to use them at all.
As a wild guess maybe if you have 32 generators running at once it tries to play 32 sounds simultaneously and the underlying sound system just isn't up to it.
Ah, OK. So one can turn off just the IC2 sounds, then? That's good to know.
I suspect that this isn't so much an IC2 issue as it is a Minecraft/Java issue overall. I'm not sure, but I'd suspect that Java does not use hardware acceleration for sound. Which is a pity, because I'm sure my sound card can handle at least 64 voices simultaneously (it does on other games).
Still is quite fixable whatever the cause is. Just go to the code that plays the sound for the windmills and put a cap on how many times that code can be activated before the last sound effect playing stops. Limit it to like 5-10 windmills simultaneously. That's a 3 line of code fix.
I'll leave that up to the programmers - which I am not. My skills lie elsewhere.
Still is quite fixable whatever the cause is. Just go to the code that plays the sound for the windmills and put a cap on how many times that code can be activated before the last sound effect playing stops. Limit it to like 5-10 windmills simultaneously. That's a 3 line of code fix.
1. It's definitely not a 3-line fix.
2. We're still trying to fix the actual cause of the problem, not it's effects.
It's comforting to know that you are aware of the issue and are working on it - and that your intent is to address the root rather than apply a band-aid solution. That's the mark of a conscientious developer. I appreciate how you stay in close contact with your userbase and take our concerns to heart.
For what it's worth, I set up a similar wind farm over another location and it seems to be fine - but, as I mentioned, I replaced the windmill .ogg with silence.
So, the problem is bigger than i thought...
hope you fix it soon alblaka, wind mills are my main source of energy 
The point is, there are enormous amounts of bugs in both vanilla and IC. Yet most are unknown and unheard of.
The issue with windmills most likely is not related to the actual windmill sound, but to the sound system (which is, given the fact it's new, highly flawed) messing something up, which becomes visible in combination with the windmill sound.
Similar to the (still existing) fatal TE-Replication bug of vanilly MC. You wouldn't ever notice it, unless you have furnace-blocks rapidly turning on/off (IC1 Watermills).
Luckyly IC²'s meta-blocks made that issue obsolete enough to be ignored again :§
