Lubuntu 20.04 Memory frequency value displayed wrong?

Using Lubuntu 20.04 64 bits and nvidia metapackáge 450.57.
GPU is GT 640 GDDR5 GK208.
In windows 10 using Precision XOC and others gpu information utilities the memory frequency is displayed being 2,5 GHZ.
In Linux Lubuntu in Nvidia X server control panel is displayed memory transfer rate value 5 GHZ.
The value 5 GHZ for memory transfer rate is correct ?
If the value is wrong how to fix it ?
Thanks for reply.