Lag problem HELP

Lag problem HELP

So, i installed Ubuntu 12.04 with all the updates needed from additional
hardware and system in dual boot with Windows 7 to raise a little the
performance of my PC. After installation, Ubuntu was slower than Windows 7
(for example it takes like 5-10 seconds to open the terminal or opening
the Dash Home after pressing it). I have a AMD Sempron with 2.0 GHz, 1.0
GB of RAM and an internal graphics card nvidia nforce 630a. It is normal
to be like this with the poor configuration or is there any conflict with
the AMD processor or graphics card? How can i fix this? Thanks!