Hello,
In short, XL version print 2 time more
I searched the same information and found this :
"With the HP 934XL High Yield Black Original Ink Cartridge, you can get around 2 ½ times more printed pages when compared to the HP 934 Black Original Ink Cartridge.
The high yield versions of the cyan, magenta and yellow cartridges can print approximately more than twice the number of pages than the normal versions.
So, although the high yield versions are more expensive, these XL cartridges also provide better value than the normal versions as you will be able to print at least 2 times as many pages."
from
https://seekingtech.com/hp-934-vs-...PS : I simply googled "HP935XL vs HP935" ;-)