I have an IBM PC 300 GL:
128 MB RAM
500 Mhz processor
Nvidia MX440 video card with 64 MB RAM.
Sound Blast 16 PCI ( emu10k )
Intel Pro 100 nic.
Unfortunately the ESS sound does not work.
I had to use a USB mouse and Keyboard as the ps2 ports quit working after Grub.
I seems to run well with Icaros 1.3.3, but it does get choppy when I want to move an application around on screen when something is running.
The patches do not do me any good, I will have to check Icaros Website.
500 MHz processor is good for standard-quality video reproduction (DVD should play fine, DivX videos with lower bit rate as well), playing music, looking at some sites with OWB, chatting with WookieChat, playing some simple games, but nothing more.
128 MB of RAM are the bare minimum to run some applications. Minimum specs for Icaros Desktop are 256, though.
GeForce 4MX is outdated and not supported for 3D part, but it should work for the 2D part.
No surprise Icaros Desktop doesn't run very well on your system. Please disable decorations in S:startup-sequence commenting out the "C:Decoration" line, disable Opaque and run the Services prefs to kill any unneeded service. Then reboot. Use also fixed IP for your local network if applicable. This should help you getting some speed improvement, even if it will lower somehow visuals. Ah, and disable also transparency in drag and drop operations.
...and please upgrade to better suited hardware if you can!