FPS lag on a relatively decent build...?

[Wuverul]

I'll just start this whole thing with specs.

8 GB DDR3 (OC'd 1600 Mhz.)

-----4GB Allocated

AMD FX-8120 3.1 Ghz 8-core CPU

Nvidia GTX 660 running at 1110 Mhz

MSI FXA-GD65 v2 Motherboard

750W Corsair PSU

(Peripherals if anyone's curious. Shouldn't make much difference but you never know)

Razer Megalodon headset.

Razer Naga Molten for a mouse.

Steelseries 6Gv2 keyboard.

Monitors:

Acer p191w 19" 16:10 widescreen (1440x900) (Primary display for Minecraft)

Westinghouse HDTV running via HDMI at 1080p (Usually disabled when playing minecraft)

I can run countless games with little to no lag (EG. Skyrim with HD texture packs, lush forest and realistic water mods, etc etc at 60 FPS) yet for some reason Tekkit Lite runs at ~20 FPS with spikes down to 5-10. This is a tower and there is no integrated graphics.

Tekkit Settings:

Graphics: Fancy

Smooth Lighting: On

3D Anaglyph: Off

Particles: All

Fullscreen: Off (although I have it taking up all but the taskbar)

Render Distance: Far

Performance: Balanced

View Bobbing: On

Advanced OpenGL: On

Clouds: On

Server Textures: On

Use Vsync: On

What's odd is I use these same (or similar) settings for vanilla minecraft without much of an issue. Both are using the default texture pack.

Note that in a pocket dimension I get ~120 FPS. In a house I also get decent FPS. It's when I'm out and about, gathering wood or mining, or sometimes even looking out a window >.>

[RalphRoberts]

One thing I can suggest is to try out optifine. Although you might want to set performance to "Max FPS" because "Balanced" can lower your maximum FPS even if your machine could otherwise handle it.

[disconsented]

The issue is likely your fist gen FX processor due their horrible single core performance.

Optifine is your best bet the only other option I can think of is the Razer GameBooster.