It's always okay to ask any question no matter it sounds stupid or not cause if you don't ask a question, you never find out
So coming back to your question now, my friend PCI-e 1x .. not much goes in those, although you can get some network cards that fit them. The slots are about as important as any other PCI slot. Its your only form of card expansion and although you can fit in a 16x cards in it but that would limit the bandwidth of your GPU since 1x does not offer much of the bandwidth. I am also not sure about the cumulative performance drops since I have never tried it myself however I think that your overall system graphic performance will be affected.
As for 16x, you can use any good GPU (Graphic Processing Unit / Graphic Card) to fit into them giving you a good resolution and display supporting a wide variety of games as well and it will also resolve your multiple display problems since most of the GPUs have DVI and VGA ports on them enabling you to have dual monitor plugged on to that.
Hope this answers your question but just in case, you need further information, you are always welcome to consult us.
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