USB peripherals stuttering when two external ssds connected and files being transferred from one to other

My PC Specs:
i9 12900k
32 g ddr5 kingston ram
Rtx 3070
850w psu
Msi z690 pro a
Internal storage -1 tb 970 vo plus and 1 tb wd nvme ssd

I have two external ssds connected - sandisk extreme and crucial x8 connected to two usb3.2 gen2 type c ports.

Following are the scenarios
1.) I am copying data from one external ssd to other external ssd.
2.)I am copying data from one external ssd to internal storage ) while the other external ssd is plugged in and idle.

These two scenarios end up having every other usb peripheral jittering that is my mouse keyboard my audio interface output. My copy speed is around 450-500 MBPS.

As soon as copy ends everything returns to normalcy.

Also when I copy data from one external ssd to internal storage while the other external ssd is not plugged in there is no jitter.

**I also tried connecting the same two drives in a friend's pc with far lower specs like i7 8th gen 16gb ram and a cheap case(forgot the name) . To my surprise, the copy ran smooth in his pc without any usb jitter **

If anyone with some knowledge on this please help.

Bruce said:

you are simply overloading the I/O bus lanes of the USB channels when you have both SSD's in play.
with one, all I/O's can be handled by the OS - with both, it has to start resource sharing and buffer the I/O's accordingly.

that fact both devices transfer fine on the other PC simply means you are not comparing apples with apples.
you don't need much processing power to transfer files, and the difference between 16GB and 32GB is also insignificant for I/O operations, and the case has no affect at all.

make sure both scenarios are using the same USB ports, these ports are the same make/model and use the same driver, both PC's have the same OS and same background tasks running, and both have the same motherboard.
and when you test the file transfer speed, you are using the same bunch of files, from the same source, to a destination of the same drive type and file format type.

Click to expand...

Thanks for the reply. I agree to the fact that my friend’s pc is not same as mine but its a lower spec model. By default it should run better on a z690 mobo like mine.