Which of these two desktops has the best performance, and quickest response, Gnome 2.10 or KDE 3.4?

it doesn't make a significant difference, both are equally slow and especially on SuSE

Just try both and then keep the one you think meets your needs and has better performance on your system.

Why are they slow on SuSE?

What are your systems specs, particularly RAM.

I am running a AMD K7 Duron 950Mhz with 384MB's of SDRAM.. also my system has a 64MB VRAM Nvidia video card.

The GUI that I am currently using is SuSE's 9.2 KDE 3.3.0 (patched) version, and it seems to run very well since my kernel adjustments. Slow... not on my machine, but I was wondering if Gnome was faster. I seem to remember running Gnome before and it was quicker, smoother graphics, and a very friendly environment to use. However, there was issues I did not like, such as GPG interface, in my opinion, it was not as friendly as KDE. I believe that version of Gnome was 2.8.. maybe... It has been a while. Hopefully with version 2.10.1 of Gnome the added features that I like will be added, but the overall of the GUI does seem appealing. I really enjoy KDE though.

In my spare time, my mind is proposing to recompile KDE 3.3.2 into athlon arch for a little more performance, and perhaps Gnome 2.10.1.

A GNOME/KDE preference is something highly personal. Personnally I think best thing is to use KDE with GNOME apps, but as I said.
KDE and GNOME are inherently slow, but I think that the amount of functionality makes it up. SuSE (and now I'll probably be flamed like hell) is very bloated, kind of like Mandrake. It contains lot's of bells and whistles you can easily live without and slow down your system significantly.
I remember something that preloaded some parts of OpenOffice when starting KDE, since OpenOffice uses quite a lot of RAM, this can slow down your pc a lot. Then try starting netbeans if you only have 256 MB RAM.

Very interesting point elluva. Do you think that the OpenOffice issue would matter if it is not installed? On my system I do not have it installed because I found that it was too slow. For office, which is rarely used on my machine, KOffice is used.

After installing packages, using Synaptic, the SuSE config spits out ooo messages that Synaptic insists on displaying. Is this what you are referring to? Nevertheless, this must be bypassed, I suppose, when using YaST2, or plainly just not displayed.

Yesterday I ordered Ubuntu 5.04 to see what that was like, but for now I am sticking with SuSE, which I do find very nice. What other bloats are there regarding SuSE? I find this very interesting due to my inner desire to have a smooth running machine.

Great input, thank-you all very much, and please keep it coming.