I would like to know what the difference is between x1 and x16?

This is from wikipedia regarding the PCIe16 slot:
PCI Express logo
Year created 2003; 17 years ago
Created by
IntelDellHPIBM
Supersedes
AGPPCIPCI-X
Width in bits 1 per lane (up to 16 lanes)
No. of devices 1 on each endpoint of each connection.[a]
Speed Dual simplex (in each direction); examples in single-lane (x1) and 16-lane (x16):
Version 1.x: 2.5 GT/s
x1: 250 MB/s
x16: 4 GB/s

Instead of saying "this is from wikipedia", it's more useful to post the precise URL.

See https://en.wikipedia.org/wiki/PCI_Express. It includes a photo of PCIe slots of different lane counts and a paragraph that explains x1 etc.

x1 uses a single data lane, x16 uses 16. This means that x16 cards in x16 slots have a high bandwith, and x1 cards in x1 slots or x16 slots are slow.

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PCIe is a multi-lane serial bus. The smallest PCIe connector has one lane, while the largest has 16.

Every PCIe device can work using a single lane. More advanced devices that require (or at least can make use of) more bandwidth can use multiple lanes.

As you can see from the Wikipedia data, a single PCIe 1.x lane can provide 2.5 gigatransactions/second, which translates to a transfer speed of 250 Mb/s. Finding the theoretical maximum bandwidth for a 16-lane connector is a simple matter of multiplying the bandwidth of a single lane by 16.

Note that a 16x PCIe connector may or may not be wired with the full number of lanes. It is entirely possible to have a 16x connector that provides 8, 4, 2, or even just a single PCIe lane. Any card that fits into the slot will still work, albeit slower if the card in question could have made use of the extra lanes that aren't actually present.

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