will ios 14 slow down my ipad mini 4

Are you sure you have an iPad Mini 4?

What is the “A” model number of your iPad Mini?

If your iPad Mini has been stuck on any version of iOS 12, all of this time, you own a 2013/2014 iPad Mini 2 or 3.

Either one of these cannot be upgraded beyond any version of iOS 12, which is currently at iOS 12.4.9.

That IPad model is too old and has underpowered internal hardware that cannot run any of the new and advanced features of iPadOS.

Sorry.

Your iPad Mini model is over 6/7 years old,,now and is too old,

If you need/want an iPad with a current iOS version with current, up to date apps, then you really need to seriously consider a new iPad model OR a “newer” , used iPad model capable of running the latest iPadOS versions.

There are plenty of newer, older iPad models that can run the current versions of iPadOS 14.

Sorry & Best of Luck to You!

Okay.

iPadOS 14 might make your iPad Mini 4 slower. It might not.

The iPad Air 2 and iPad Mini 4 are at the bottom of Apple's iPadOS compatible hardware.

So, it is up to you what you wish to do with your iPad.

iPadOS 14 has lots of new features that you will miss out on, if you decide not to upgrade

Also, by upgrading, you receive the most current app updates, as well as, current Apple iOS and security updates.

You miss out on new iPadOS features like:

Mouse/trackpad support

External drive support

Improved multitasking

Improved Siri

Support for installation of third party fonts.

New, improved default Apple apps.

Just to name a few.

iPadOS is a game changer for iPads.

The decision is up to you.

Best of Luck to You!

Your iPad Mini 4 would have run faster IF it has a sufficient amount of internal, free data storage space

You should never, EVER completely fill up any computer or computing device with data!

If your iPad Mini 4 was NOT a 16 GBs one, and either a 32, 64 or 128 model, you shoukd always leave, at least, 3-4 GBs constantly left for free, internal data storage space to insure/ensure the iOS/iPadOS runs at an acceptable or nominal to normal performance level.

Ideally, if it is possible, leaving 5-6 GBs of free, internal data storage space that will insure iOS/iPadOS runs fine with a minimal reduction in overall speed/performance.

Note.

An 16 GBs Apple iPad after drive formatting and installing of more recent iOS/iPadOS versions will eat up anywhere between 4-6 GBs.

So, a 16 GBs iPad will start out with an initial, usable, practical storage space of ONLY 7-9 GBs.

With the 3 GBs free space reserve, this ONLY leaves between 4-6 of usable data storage space AND THAT IS IT!

A

32 GBs iPad is much better leaving you with a usable 18-20 GBs of data storage space, after drive formatting, installation of iOS and a 3-4 GBs free data storage space reserve!

A 32 GBs Apple iPads has over 3-5 times the amount of usable data storage space of a 16 GBs Apple device.

This is why in late 2016, early 2017, Apple did away with all 16 GBs storage devices in a quiet, silent admission that a 16 GBs device by 2015/2016 was not a visible data storage option any longer.

Really today, with iPadOS getting larger and larger, the really minimal, usable, base storage for any Apple iOS today, is really w 64 GBs device as this will give you about 50 GBs of practical, usable data storage space which is 2-3 times the intern; dtw space of a 32 GBs Apple storage model and about 10-12 times the amount of a 16 GBs Apple storage device.

Yes. Mine is really slow. I bought mine since it was first released. Already switched to mini 5. Much faster now.