Guide
Graphics card running x8 instead of x16? How to check and fix it
A graphics card talks to the CPU over PCIe lanes. The fewer lanes it gets compared with what it has, the slower the data moves and the more FPS the game loses. You can't see it from outside: the PC boots and games run, just slower than they should.
First check how many lanes your card has
Some cards only have x8 from the factory, even in an x16 slot: RTX 3050, 4060, 5050, 5060, GTX 1630, RX 5500, 6600, 6650, 7600 and Arc A310, A380, A580, B570, B580. RX 6400, 6500 and GT 1030 have x4. If your card is one of these and gets that many, it is normal and needs no fix.
Why a card gets fewer lanes
- A lower slot: the lower long slots of many boards only give x4 or x8.
- A riser cable for a vertical mount: an old, loose or unsupported cable makes the card drop lanes.
- An M.2 drive sharing lanes: some boards give part of the graphics slot's lanes to certain M.2 slots. Check the board manual.
- The board or CPU only gives that much: some smaller boards and CPUs don't give the graphics slot a full x16.
How to fix it
- Move the card to the top long slot, the one closest to the CPU.
- Using a riser cable? Try the card straight in the board first. If it gets all its lanes then, the cable is the problem.
- Already in the top slot and still short? Look in the board manual for the M.2 slot that shares lanes with it and move the SSD to another slot.
- Still short after that? The board or CPU really only gives that slot this many.
Let Savenz Optimizer check it
The Home page of Savenz Optimizer reads the lanes the card really gets against the lanes it has, and only warns when it gets fewer. Cards that are x8 by design don't get a false warning. It only reads, and it works while the card is idle, so no game needs to run.