These connectors are all keyed so they’ll only set up a method, the proper means. If the video card has auxiliary power connectors (labeled PCI-E) connect the appropriate energy supply cables. There are 6 and eight pin PCI-E connectors, some cards have each, some energy supplies have both. Other power supplies could have “6+2” which can be used both way, like the 20+4 ATX and 4+4 CPU connectors. Connect a monitor with a VGA or DVI cable to the video port on the board or video card and turn it on.
Computer Science