Is it true that USB sockets in the rear get more power supply than those in the front ?

Front ports are passive hubs that only have 100MA for each port.  The rear ports are active and have 500MA for USB2 and 900MA for USB3.  The exception is thunderbolt which can have up to 100W of charge power.  Specific models have thunderbolt.

Re: I hear that USB sockets in the rear get more power supply than those in the front.

which Vostro desktop model?  Newer Vostro has front USB port integrated in mobo, while old Vostro model had separate FIO port connected to mobo via usb 9pin cables

Thanks  redxps630

Vostro 3690. I bought it last year.  It seems to be made in 2021.

Vostro 3690 ● Two USB 3.2 Gen 1 ports (front)
● Two USB 2.0 ports (front)
● Two USB 3.2 Gen 1 ports (rear)
● Two USB 2.0 ports (rear)

Dell has not released power rating spec.  one way you can test yourself is to charge a smart phone on front and back USB and test for obvious charging speed difference.

Dell-Chris M may have inside engineering info that non-Dell users are not privy to.