Yep even if the scn svr version is optimised the CLi/SETIDriver is still about 25% faster ,not to mention that SETIDriver can store WUs for you too (incase the S@H servers go down).
To optimise the GUI(scrn svr) version you need to make sure that the graphics don't show ,at least not for long.
If you have it set to 'always run' only then you just need to minimse the window when your not looking at the pretty graphics😉
If you have it set as a screensaver then you need to go to display properties,screen saver,screen saver settings ,then tick 'blank screen' & set it to less than 6mins.
Doing that will avoid doubling WU times!:Q ,though the CLi is still faster like I said😉