Ok the card you linked to is PCI, it will fit in any PCI slot, even though it has the extra space, 3 pins as you say.

Your second link shows 4 PCI slots white, and one AGP slot brown.
none of these are PCIe.

Good luck.

your graphics card has the old PCI interface and the interface on your motherboard is the newer PCI express interface (x16)…. you need to buy a newer graphics card for PCI-Express.

gl

Standard PCI slots are white! PCI-e (enhanced PCI bus) slots are brown! ;-)=

This is very simple. On your Dell the white slots are what you call PCI Express slots. The Black PCI slot is called the PCI Express X16 which is used for graphics cards. It will work fine in the black slot so don’t worry. Good choice in graphics card though!