I wanted to run 3 monitors on my PC but it only had a single video card slot. That meant I could only run 1 video card and a single video card usually only supports 2 monitors. Some high end cards support 3 or more monitors but of course I wanted to do this on the cheap! I'd heard it was possible to install a second video card by cutting most of the pins off a 16x PCI Express card and installing it in a 1x slot. It sounded like a bit of an internet myth but it turned out to be true and has been running in my PC for many months.
The photo below shows the available slots for my motherboard. The blue one on the left is the 16x PCI Express slot that takes a video card. The next 2 slots are the old style PCI slots. Installing a video card in one of these slots would be possible but I don't have one, they can be hard to come by and tend to be very old cards. The 4th much smaller slot there that is labelled "PCIEX1" is the PCI Express 1x card. This is effectively the same as the blue slot except cut short. A video card won't physically fit in this slot because its pins are much longer. However, it is actually possible to simply cut the extra pins off the card and it will work.
Step 1: Marking the location to cut
The first step is to obtain a PCI Express video card. Decent cards can be obtained from ebay for around $10. Before cutting anything it's a very good idea to mark the pins that should be cut off. We want to cut all the pins off the larger section of the card except for the first 7 pins. In the second pic here I've used a marker to mark the 8th pin. This pin and everything to the right needs to be cut off.