One drive always backs up slowly

[daystrom]

Case # 0772561

My pc has 4 internal storage device, all are 2.5" ssd, except for the boot drive which is an m.2. The e drive always backs up at a much slower pace than the other drives. I have switched the ssd out multiple times, using different brands of ssds, all 2 tb. The e drive contains mostly vm files which are larger than most files, but those should back up faster not slower. The drive is fairly full, 8% free. None of the files on the e drive are in use when I back up. The backup target can be an internal hdd or an external usb connected hdd.

The other three drives report file transfer speeds between 125 mb/s 240 mb/s, the e drive reports 19 mb/s

This issue has persisted for years, it's a real pain. A full backup to external drive takes at least 24 hours because of this one particular slow drive.

Veeam Agent 6.3.1

Why does that drive back up so slowly, regardless of which ssd it is located on?