Usb 3.0 pcie card not running at Usb 3.0 speed ?

  pcgeektypeperson 09:11 13 Jan 2017


I have a usb 3.0 pcie card installed on my win 7 pro 64 bit system. It has installed properly but only running at usb 2.0 speed. It did 'once' run at 114 mb/s then slowly went down to about 26 mb/s

Could this be a bandwidth limitation on my motherboard ? Ive looked in bios setup, usb 2.0 mentioned but no mention of usb 3.0, it probably did not exist when the motherboard was manufactured.

Thanks, Mick

  Archonar 10:15 13 Jan 2017

I suspect it will be a motherboard limitation, if the motherboard was created before cards were using the speeds of USB 3.0 then the port may well just not be able to give you the speed.

  pcgeektypeperson 11:05 13 Jan 2017

Thank you for your reply. Yes im now thinking this too, I could look at the manufacturers website to see if theres a bios update for the motherboard but this is now my second card and I think it may be time to accept that it just wont work.

Thanks, Mick

  Bris 11:20 13 Jan 2017

This may be due to limitations of your motherboard i.e. the version of PCIe that it has. If the card is plugged into a x1 slot and has the capability of using more than a x1 slot try plugging it into a x2 or x4 slot if one free.

I doubt its a BIOS issue as the card is plugged into the PCIe bus and therefore is governed by the driver being used by the OS.

Also it will be sharing bandwidth with other devices plugged into the bus such as your graphics card which could slow it down.

  pcgeektypeperson 12:45 13 Jan 2017

Many thanks for your reply. The board has 2 slots, ive now tried both, the second one a bit slower than the 1st but both not much more than usb 2 speeds. Sometimes the card starts at 65 mb/s or even maybe over 100 mb/s but always slows back to between 20 and 26 mb/s.

I think this means the pcie bus just cannot handle faster speeds, or the system is throttling the speed. Graphics card is built in chip type, not a gaming card by any standard and theres not much else drawing on the system.

I think stores selling these should point this out to people before letting them buy one.

Thanks again.

  pcgeektypeperson 13:20 13 Jan 2017

Update, both pcie slots are only pcie x 1 slots. Maybe that was the problem. Anyway i am returning as there was no advertisement warning to check motherboard specs. I will just use usb 2 slots and usb 2 drive caddies.

Thanks for the help, much appreciated.

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