since compiz is using too much resources in ubuntu 14, i wish to remove it.I'm worried if that would result in affecting unity?(i don't need the fancy visualizations)
The simple answer is Yes - removing compiz from Ubuntu 14.04 will affect Unity - in-fact it will remove Unity.
You need to understand that Unity on 14.04 is basically a very large Compiz plugin.
Lets have a closer look without affecting your current install:
This is a simulated removal - nothing will actually be removed:
As you can see - say bye-bye to Unity if you remove compiz.
Given the gist of your question - you perhaps dont have the optimal graphics card and/or driver for this graphics card.
You can check this via this Q&A to see if your graphics card is supporting Unity-3D - any no answers means that Unity is running sub-optimally.
If you are using and AMD or NVIDIA graphics card you should check if there is a proprietary driver available to be installed. This can greatly help with complex animations & transitions that Unity require.
If after these checks you still want to reduce the Compiz effects, then we've already got a brilliant answers for this - try some of the suggestions to remove the more complex animations such as Compiz Blur.
Alternatively, you may wish to try a lighter desktop environment that is more suitable to your hardware. Suggestions are xubuntu and lubuntu - both of which you can install straight away - you dont need to remove your current installation.