Problem Strange server lag

[James Sidney]

Hello.

First things first, I'm running Windows 8 and I'm hosting the server on the same computer I'm playing it on. I'm running FTB version 1.2.4 on Minecraft version 1.4.7. I have added two mods to the modpack: BechillTPS and TickThreading. My computer has 16 gigs RAM, an AMD Radeon 7800 series graphics card, and an intel i-5 3570k processor. Running the server, client, and Firefox, I'm at ~55% CPU usage and 37% memory usage.

I was experiencing the lag before the installation of the two mods, and added them only to see if they would help and to provide diagnostics. My problem is that I'm experiencing significant lag but I do not know why. The server GUI says my avg tick is ~2 ms, typing /tps in game (a BechillTPS command) says I'm getting 20 TPS, but my engines still jump around, mobs have a hard time moving, hits register slowly, and EU generation is jumpy instead of smooth.

Up until now the server was quite stable. EU generation slowly got more and more stuttery, but until today mob interaction was perfect as far as I could tell, and engines flowed nicely. Furthermore, it may be worth noting I have no FPS lag. My upload speed is currently 2 MB/s.

Any insight into the matter is appreciated.

EDIT: I just tried running the world without the server (on single player mode) and it ran just fine. Perhaps the issue is with my upload speed? I had assumed 2MB/s was high enough, but perhaps not?

 

[tvoid]

Are you limiting the BW between ur client and server even though you are running them both on the server hw ? The 1st thing that came to mind with your setup is that you have the client and the server running from the same physical HDD (not talking about partitions). If you have anything less than 3Gb/s SATA3's you migh get lag. (seek time can also cause this). So before i blabber on about why it can be the problem, please let me know is your client and server sharing the same physical HDD and are you limiting the bw between ur client and server ?

 

[James Sidney]

I haven't explicitly set a limit on BW, if one is enabled by default though I haven't changed it.

And yes, both the client and server are on the same SSD. Now, my SSD says it's interface is "SATA 6Gb/s" and the "Sequential Read" is "Up to 530 MB/sec " while "Sequential Write" is "Up to 130 MB/sec ." My HDD says the "Maximum External Data Transfer Rate" is 4.7 Gbps. I'm going to move the client on to the HDD and see if that fixes it. Unless you have a better idea? Good thinking btw, I totally overlooked this!

Also, I've heard that Minecraft is only capable of being run on a single core. Could it be that my server and client are being run on the same core and capping it out? Is there any way to ensure that the client and server are run on separate cores? Or is this info false making this a non-issue?

EDIT: After moving the client to HDD and keeping server on SSD, there was no noticeable improvement. I downloaded a fresh server without the two mods added mentioned above, and again no noticeable improvement. I'm going to try accessing the server from a client on another computer right now.

EDIT2: Trying it with only the server running on this computer and accessing it on a client running on another, there was a small noticeable improvement but it was still unsatisfactory. I've also tried giving the server more RAM, up to 2 gigs now.