Have to agree with Jdrou on the vid and also mem and chip. I have not seen these problems, and on one machine I am using an old AMD chip (850 mhz), and only a 16 meg vid card (though it is a good one -Nvidia), with only 386 Ram SDR! (Paradoxically, this machine has a huge HD-but this is what comes of scavenging I suppose!).
Unless your video card is more retarded than the one on my old scavenged machine, it is more likely that it is either drivers as Jdrou supposed or a sound card or driver for same. This is especially likely if you have a non-onboard, low-end sound card. Weird but true, sound cards can be the death of game performance, and often are at the root of display issues as well.
Also possible you got a corruption during install or updating or somehow during a save. Reinstall should have taken care of that though.
An unlikely but rare possibility is that there is something about the 104 update that is interfering with something that you have running in the background on your machine that we don't have (though to be honest I haven't any idea what that might be and you can only test it by methodically eliminating the background progams from your task manager to see if there is any effect... -er, DON'T remove systray or exlorer!!!).
Lastly, if Steel is right and there is something that happened in 104 causing a mem leak when interacting with the Core mod, I know I know, you removed it from the sys, but did you remove the Reg entry?
On AMD and other chipset-makers, typically these are easy to find on the mfg sites usually under support downloads or whatever passes for the same on their site. An exception is AT whose site and driver updates leave much to be desired. Let me know if you need AT (hope to God you don't) and I will help since our organization has more experience with navigating their site than they apparently do themselves.