MicroSDHC Ultra Class 4 is the exact same (speed) as normal SDHC Ultra Class 4?

Memory Cards SD | microSD | CFast | CFexpress | CompactFlash
1

This:

http://www.sandisk.com/products/mobile-memory-products/sandisk-mobile-ultra-microsd-microsdhc

and this:

http://www.sandisk.com/products/dslr/sandisk-ultra-sdxc-cards

And this Class 6 is faster:

http://www.sandisk.com/products/camcorder/sandisk-extreme-hd-video-sdhc-cards

than this Class 6?

http://www.sandisk.com/products/camcorder/sandisk-video-hd-sdhc

By how much?

Class ratings mean nothing. Confusing.

2

yes and yes, both comarisons you ahve there are the same speed. 

on the first one you are comparing a micro sdhc card to a regular sized sdxc card. these are 2 different form factors as well as different technology so make sure you check compatiblity with yiour host device.

the second comparison the cards are the same just changed lables. got to love when marketing does this.