I just purchased a Raspberry Pi 4b with 4 GB of RAM. It came with a power supply and a 16 GB microSD card with Pi OS (Raspbian) pre-installed. I started it up and ran through the initial configuration.

I'm using a corded USB keyboard and corded USB optical mouse. The mouse and keyboard input is so slow and choppy that this thing is completely unusable if the UI is needed. The keyboard doesn't respond. After waiting, I see it did collect my keystrokes, but it doubled some of them. The mouse movement makes it impossible to find the edge of a window to resize it or to find menu items. The cursor will stop visibly moving, but it still picks up what the mouse is saying, so by the time I stop moving the mouse I'm way past the target. It takes several minutes of precise movements and waiting to hit a menu item.

I finally managed to get a terminal open. This feels like the computer is overtaxed, but "top" tells me that I'm using about 128 MB of the available 3828 MB of memory and that the CPU is not busy. So this is clearly not because of resource problems.

I have seen other posts about this that have answers that say a better power supply is needed. Mine states the output is 5.1V 3000mA, and I think that's what I need. Plus, those questions appear to be about using wireless or bluetooth keyboards and mice.

I don't know if it's related, but it takes this unit several minutes to boot. I have also seen posts about this stating that faster storage will solve the problem. I don't see how a slow SD card can cause the computer to not pick up mouse movement in a timely manner.

I ran the Raspberry Pi Diagnostics SD Card Speed Test and got these results:

Raspberry Pi Diagnostics - version 0.9
Fri Oct 29 14:50:41 2021

Test : SD Card Speed Test
Run 1
Sequential write speed 18290 KB/sec (target 10000) - PASS
Random write speed 843 IOPS (target 500) - PASS
Random read speed 2317 IOPS (target 1500) - PASS

I posted this question yesterday, then deleted it because rebooting seemed to solve the problem. Another reboot, and the problem has returned.

Has anyone else here seen this behavior?
Are there settings I can change to get around this?
Did I get a faulty Pi?

  • write your own sd with the latest raspberry pi os.
    – Abel
    Oct 31, 2021 at 15:01

1 Answer 1


I finally found a statement about this in an article on raspberrypi.com. I had swapped out the card that came with my Pi400. It's a class 10, U1, A1. The card that came with my 4b kit was only a class 10, U1. Apparently, A1 is truly needed to run Pi OS (raspbian). I bought a better card (the one pictured in the article), plugged in a card reader and the new card into the Pi 400, ran the SD card copy utility, and my new 4b kit is running fine.

Lesson learned: Be sure you know what card is included in the bundle, or DON'T BY THE BUNDLE. (I hesitate to say which vendors I used for each purchase since this is not a vendor review site.)

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