Somehow a bunch of horses spawned in my brothers minecraft 1.6.4 game. It is too laggy to kill anything and you can't use /kill @e[type=EntityHorse] until 1.8. He worked really hard on it and doesn't want to reset it. And if you are asking, the reason he is using 1.6.4 is because he is using the technic launcher modpack "Attack of the B Team" Thank you for reading this whole paragraph!
There are 3 things you can do:
- You can just bomb the area with poison/instant damage splash potions
- You can open the world in MCEdit (which is a phenomenal tool in case you are not familiar with it) and remove the horses from there. It won't be able to correctly render the modded-in blocks and entities, but as long as you don't touch anything except for the horses it should work just fine.
- You can go to your Minecraft saves directory (
~/Library/Application Support/.minecraft/saveson Mac) and copy your save to another, stronger computer (maybe ask a pal to contribute his machine for you noble task?) and try to get a higher frame rate there.
Hope this helps!
If he is in singleplayer, attempt to lower the quality as much as possible (in video settings) and try to kill them.