Problem My FTB server is lagging as hell (100~300ms)

[asafor6]

Yesterday I tried playing FTB with my friend so I opened a server and it lags for my friend but not for me cuz I'm the host.
I really wanna play with him but we can't because of those stupid lags.
Please fix it for me..
PC specs:
Core 2 Dou E4500
Nvidia GT 630
4 GB DDR2
10 Mbps (the internet is not slow at all)
When I open a server on bukkit it doesn't lag, only on FTB.

 

[Velotican]

Unfortunately your computer may simply be too slow to handle the strain of being a server and letting you play at the same time.

 

[Sayomie555]

FTB takes a decent amount of memory to run, your computer does not have enough to run it as well as run your own client as well at the same time. The ftb server that I run has 16 gb dedicated to and ive seen it take 12-13 of that while running before.