Difference between system hookdll and mirror driver?

[Aguilabrava]

I have a question. I downloaded and installed UltraVNC 1.0.8.X as server in one computer and as a viewer in the other, both computers in my LAN. When I open "Edit Settings" in the server computer and I go to the Screen Capture tab, under Advanced it shows two options, one is to "use system hookdll" and the other one is to "use mirror driver" which I have installed and it shows under Display Adapter in my Device Manager, right on top of my regular Nvidia video driver for my video card.
What's the difference in using system hookdll or the mirror driver?. What are the advantages and/or disadvantages?. What happens if I don't select either of them?.
I ask this because I did some tests, when I used the "mirror driver" and there was a webcam connected in the server computer, I couldn't see the image captured by the webcam in the viewer computer. I went back and changed it to use "system hookdll" and now I can see the image captured by the webcam, but the refresh rate is very slow, I have to click "refresh screen" in the viewer in order to see changes in the webcam captured image in the server. Is there a better way to do this?.
Thanks.

[redge]

faq
[topic=15864][/topic]

i won't use mirror driver on vista/7 for this reason and eliminate border side issue with another driver limitation.

experienced just today.
i have very good result of video rendering.
win7 winvnc 1.0.9.3.3 MultiCPU with only system SCHook and ultravnc viewer 1.0.9.3.3 MP with best result with lossy quality video tight codec, very fast with full color and watching 640x480 video youtube via 2Mbit Internet

zrle is a lossless codec and slower if not optimized multi CPU/thread

but you need to wait build uvnc 1.0.9.4
(http://www.uvnc.eu/download/UltraVNC_1. ... _MP_update is not available)