These are the tweaks Unofficial SP3 does:
HKLM,"Software\Microsoft\Windows\CurrentVersion\Explorer","Max Cached Icons",,"2048"
%30%\msdos.sys,options,,"systemreg=0"
System.ini,386enh,,"ConservativeSwapfileUsage=1"
System.ini,386enh,,"DMABufferSize=64"

You can check which one was causing all those problems for you.

If Tweaks do only these simple thing, it should be easy to debug.. I expected that is much bigger package, or even whole SP3.. Because them i did some networking change i saw that source of files which were autocopied so SP3.cab.

Its long time when i last time fiddle with SP3, is there some way how to install/ uinstall  just these tweaks alone?

We can exclude icons, first row. 
I dunno what second row does.
Third row is a swap, small change. Only if some part of networking driver would be somehow swapped and driver does not expecting that..
I would bet on 4th line, if Network cards are using DMA, im not sure.. I know that videocards and soucards are using DMA, probably even some TV and Capture cards, but im not sure about NICs, i never saw some DMA settings for them,
maybe drivers just do it. I there is some PCI Bus driver which are interacting with NIC and using DMA..