I have recently installed Ubuntu 13.04 on my PC, and it's quite slow. I'm not sure what is causing the trouble, but it looks to me like it's Unity, because all the applications take a long time to start.

I have an Intel Core 2 Duo 2.2 GHz CPU and 1.5GB RAM. I don't have any extra graphics or video card installed. And from what I have read I know that Unity uses a lot of GPU if there is a GPU installed. So if this is the cause of my poor system performance, would switching to a new desktop environment be advisable? Do you have any other suggestions for how to improve my system's performance?