Unity runs slow, how can I improve its performance?

I like how Unity looks but I have 2 problems:

1. Unity 3D
   When I login with Unity 3D, my pc becomes slower, I got an AMD II X3 with 2GB of RAM, Nvidia Gforce 6150SE nForce 430/PCI/SSE2 integrated.
   When I try to open the dash, take a lot of time to open, most often takes up to 5 seconds and while its opening remains fuzzy and unreacted, even the apps or folders take the same time to open and the same reaction.

2. Unity 2D When I login with Unity 2D my pc goes more faster, the only problem is that i cant configure Unity as I want, I try to configure the Unity plugin in CCSM.
   For eg: I changed "hide Launcher" to: Never. It does not save changes, even when I restart my computer.

I don't know if the problem is with Unity 3D or with my pc.

In CCSM, go into the options for Ubuntu Unity Plugin and in the tab Experimental, change option Dash Blur from "Active Blur" to "Static Blur" or "No Blur".

You can also go into option Composite and disable "Detect Refresh Rate" and increase option Refresh Rate to over 60.

To increase performance further, you have to have Nvidia's propietary drivers installed (make sure you are using the latest version). Go into NVIDIA X Server Settings and in Open GL Settings Change "Image Settings" to "High Performance".

Remember these options will only apply with *Unity 3D*

You cannot ust CCSM to configure the Unity-2D since it is not using compiz to show Unity. You have to use dconf-editor or you can use this tool :

http://www.omgubuntu.co.uk/2011/04/ubuntu-unity-2d-tweaking-tool-lets-you-adjust-the-launcher-dash-enable-compositing/

Hope this helps.

Luis Da Costa