Unusual Lag problem?

[Lyiin]

I'm experiencing an unusual lag problem, and can't seem to find a way to permanently fix it.

First off, I host a Tekkit server and play on a client on the same laptop, and my specs should suffice:

8GB RAM

Intel Core I7 processor (2.3 GHz)

Windows 7 64-bit

NVidea GeForce GT 650M (1GB) Video Card

I also have the latest version of Java and Tekkit installed.

The strange thing about this lag is that it goes away whenever I change any of the video or performance settings, then returns after about a minute or so. It doesn't matter what I change, nor does it matter to what value I change things.

For example: because of the lag, I had set my render distance to short and graphics to fast. After about a minute, the lag started to increase again, and I turned the render distance up to Extreme and set the graphics to fancy. The lag went away for a minute, then returned.

I've tried countless combinations of settings, but none of them were able to get rid of the lag permanently.

My CPU and RAM usage hardly ever exceed 50% (usually, CPU usage is at 14%, and RAM is at at 3,4 GB). The other players in my server aren't experiencing any lag.

Does anyone know of a way to fix this problem? Any other information you might need?

[Torezu]

You have a very nice laptop. There's a very high chance you're not using the NVidia card for your copy of Minecraft. Go into your NVIDIA Control Panel, and set your laptop to use the high-performance card for Java.

[Lyiin]

Thanks! I've changed some settings and am now running Tekkit using the NVidia videocard, and my framerate has never been so high!