I don't know if many here are running Zorin, you may have better luck with support here if you were running Ubuntu, Kubuntu, Mint Cinnamon, Mint Mate, Mint Xfce. Zorin looks pretty standard Ubuntu though so maybe it won't matter, I found it hard finding info on it.
All of the distros that pcpunk mentioned above (in general) works better with most computers, because Zorin OS charges a premium (masked as a donation) to provide 'premium' drivers. While most Linux distros does this by default, each has their choice as what & what not to bundle, to include the latest/best drivers for one's system. Also, in my over 8 year experience, there's nothing wrong with enabling the CPU and/or GPU's proprietary drivers when offered. Other brands of OS, to include Windows/Mac, does the same, although this is often bundled with the normal updates.
BTW, I see that you're using AMD graphics, you'll need a distro based upon Ubuntu 14.04 to have the best experience, this covers many distros, to include Mint 17.3, supported through April 2019. You're relying on open source rather than proprietary drivers & this could well be the cause of graphics stuttering, as long as the computer is otherwise healthy. As to the fan reading you're hearing, yet not seeing, this is because one has to configure things to where these are shown. Since it's been some time I went through these, best to open another Topic on that issue, as long as you knows any are working, that's what counts. You can see your CPU/GPU temps, meaning that along with your ears, these are running, otherwise would be getting a warning at boot that the fan isn't running.
Note that with some motherboards, especially notebooks, fan control is hard to accomplish, as well as the MB reading that shows 'N/A', which applies to many desktop computers also.
I'd say going with Ubuntu 14.04/Linux Mint 17.3 is your best choice for AMD graphics at this point, although in another 19 months, will be in the same spot again when these becomes unsupported. This is where having a Intel computer with optional NVIDIA graphics can be of great help, there's no gap in proprietary driver support, one can enable these through the same Additional Drivers tab.
Now that you're empowered with a little more information, you can now test distros based from Ubuntu 14.04, if desired, can do so from installing to a 16GiB or larger USB stick first. While you can grab some updates in a Live session, drivers are different, the required reboot will undo what you've enabled. THis is where an install directly on a USB stick can help, although keep in mind to place the bootloader on that stick & not your internal drive. You'll see the option when creating partitions, at the bottom, there's a drop down menu as to where to select the bootloader's place, choose the USB stick. Of if easily accessible, remove your internal drive to ensure nothing becomes overwritten (my preferred choice).
Good Luck & please let us know the outcome in this Topic. The usefulness of our answers means a lot to the Community as a whole & allows us to improve our quality of service to others.