PCI Express Cheatsheet
I keep having to look this up, so I just made this cheatsheet instead.
The speeds listed below are per lane. This means you will need to multiply by the number of lanes to get your total bandwidth. E.g. x PCI-e x4 = 4 times as much. Speeds are specified in gigatransfers per second and MB/s. This is because the MB/s is what you will actually get out of it due to overheads.
- 1.0 - 2.5 GT/s - 250 MB/s - enough for a 1 gigabit NIC
- 2.0 - 5 GT/s - 500 MB/s - good enough for 4 hdds or a 4 port gigabit NIC.
- 3.0 - 8 GT/s - 985 MB/s - 2 or 3 SSDs
It is worth remembering that:
- plugging a PCI-e 2.0 card into a PCI-e 3.0 slot will always work at 2.0 speeds.
- Just because the motherboard slot is x16, and so is your card, that doesn't mean it will be given x16 bandwidth. Often the second PCI-e x 16 slot is only given 8 lanes or possibly even less depending on what else you also have plugged in. This depends upon your motherboard and is worth referring to the manual.
First published: 16th August 2018