[Help Please Severe Lag (MAC)]

anyone have an idea about this?

[Help Please Severe Lag (MAC)]

Hey guys my friends and I just recreated a new minecraft server using Tekkit. LOVE IT! I'm using my macbook pro

Processor 2.9 GHz Intel Core i7

Memory 8 GB 1600 MHz DDR3

Graphics Intel HD Graphics 4000 512 MB

Software OS X 10.8.3 (12D78)

I reverted my Java to 6 like I saw on the forums because of the crashing Java 7 caused hoping it would solve my issue.

My Issue: Since switching to tekkit I have extreme lag, I know its not my internet and I don't think it's my computer because I didn't have these issues when using the normal MC. My brother also plays on the server and he has no real lag issues. I will get really bad lag 10-15s and just jump around the map and it makes it impossible to kill monsters or really do anything. If anyone has a way to help it would be greatly appreciated. If you require further information please ask and I will provide. My settings are all turned off or as low as possible in the MC video settings, and I use Tiny distance

Thanks