Problem Monster pack server

[totte1015]

So I am currently running a home hosted server for me, and for a friend to get to know a few mods.

First time I cranked the server up, and then my client to join myself, he got on too, and we played and he was very suprised that there was no lag, and neither for me.

But now, second time I did the same procedure and now it lags like hell for me, my whole computer is not keeping up when i write, the cursor is lagging and the client FPS is fluctuating like hell.
ALTHOUGH, my friend is on the server and it still gets no lags for him!
Shouldnt it actually be the other way around? xD

Anyway, is there any steps I can do to remove the lag, and yet have a good server going?

My specs:

Operating System
Windows 7 Professional 64-bit SP1
CPU
Intel Core i5 2500K @ 3.30GHz 55 °C
Sandy Bridge 32nm Technology
RAM
16,0GB Dual-Channel DDR3 @ 799MHz (9-9-9-24)
Motherboard
MSI Z68A-GD55 (G3) (MS-7681) (SOCKET 0) 28 °C
Graphics
BenQ G2420HDB (1920x1080@60Hz)
3071MB NVIDIA GeForce GTX 780 (ASUStek Computer Inc) 46 °C
Storage
698GB Seagate ST3750528AS ATA Device (SATA) 35 °C
232GB Samsung SSD 840 Series ATA Device (SSD) 37 °C
Optical Drives
HL-DT-ST DVDRAM GH41N ATA Device
ELBY CLONEDRIVE SCSI CdRom Device
Audio
Realtek High Definition Audio

 

[Connor Gavitt]

For starters, FPS has nothing to do with the server.

Now if you are running the client and server on the server computer I don't suggest doing that as most computers cant do that without lagging. So are you using the client on the server computer or is your friend?

 

[totte1015]

It did work first time :/

I crank up the server with the .bat, then i just launch FTB as usually

 

[Connor Gavitt]

It seems then that your computer can't do both the server and the client applications at the same time, you could get hosting from a remote host though, or use another computer for either the server or client.