DU - why is it important?

[ArthurCorwin]

I see a lot recommended using DDU before installing a new GPU. Geometry VibesWhy is that? If you have Nvidia card and install a newer card, why should DDU be run?
Please help me understand since i have not run the program but doesn't seem to have any problems

[Wagnard]

I see a lot recommended using DDU before installing a new GPU. Why is that? If you have Nvidia card and install a newer card, why should DDU be run?
Please help me understand since i have not run the program but doesn't seem to have any problems

Why it's recommended when changing GPUs:
Even when upgrading from an Nvidia card to another newer Nvidia card, sometimes:

Old driver files, settings, or profiles from the previous card can interfere with the new card.

Windows might auto-install an old or wrong driver in the background (especially if you connect to the internet during the hardware swap).

There could be hidden settings optimized for the old card that are now wrong or suboptimal for the new card (e.g., different clock speeds, power profiles, or resolution settings).

Using DDU guarantees that the system treats the new card as a clean install, ensuring:

No old driver conflicts.

Best performance from the start.

Fewer weird "phantom" issues like random crashes, black screens, or instability that are very hard to diagnose later.

Why you might not have had any problems yet:

NVIDIA’s newer drivers are actually very good at handling hardware swaps between their own cards.

If you went from, say, an RTX 3070 to an RTX 5070, the driver package probably already includes support for both, so Windows just "picked up" the new card without conflict.

Sometimes, everything seems fine — but minor things like random event log errors, slight instability under heavy load, or features like DLSS not behaving properly can show up over time if there was leftover junk.

Bottom Line:

Is it mandatory to use DDU? → No.

Is it best practice if you want to be 100% clean? → Yes.

If your system works perfectly after the swap without DDU, you don’t have to do anything.
But if you ever face weird GPU-related issues down the road, running DDU and reinstalling drivers cleanly is one of the first troubleshooting steps people recommend.