I am new to Linux and have tried several Ubuntu 14.04 versions. For about 3 weeks I loaded version after version on my laptop and I finally chose Kubuntu and like it, but why does the Ubuntu Desktop video driver work so agonizingly slow compared to all the others I tried. I have an older IBM Laptop that runs a Radeon Mobility 7500 video card. Lubuntu, Kubuntu, Xubuntu, Mint, Gnome and Peppermint all ran faster and all use the same Ubuntu 14.04 as the basic engine and just run different GUI's, if I understand it right. Of course, the one I wanted to use was Ubuntu Desktop and it just did not like my computer. I guess my question is, why do all Ubuntu 14.04 versions not use the same video drivers? I really wanted the only one my computer did not get along with.

How old is the laptop? This may be xorg issue with an unsupported graphics card. They stopped support for many older cards, you may have better luck with the open source driver.

To be sure, can you give more info on the specs of the PC, even model number, ram, etc... can tell more then.

It's an IBM Thinkpad R40, model 2681, mfg date 04/03.
I have upgraded it to an 80GB HDD and 1GB of DDR Ram.

I think Ubuntu is way too heavy for that system. Also, the graphics card is unsupported by Xorg so you should use the open source radeon driver. I would recommend you stay with Lubuntu if you want to stay in the Ubuntu family. You may want to give AntiX a try. It is very light on resource usage and has a great desktop as well. There are other lighter weight distros you could try as well, like Crunchbang.

What were you looking to use the laptop for primarily?

I mostly use my laptop for home personal use but I do use it for storing work related manuals and schematics. I will look into AntiX and Crunchbag. I have not heard of them before so it might worthwhile to check them out.

Thanks for your assistance in this matter.