Someone at Blizzard accidentally updated (and then removed) on their webpage the system requirements for Android tablets. It said briefly:
- Hardware 6-inch screen or larger
- Operating System Android 4.0 or later
- Memory 1 GB RAM
The following devices are verified to run Hearthstone well:
Amazon Kindle Fire HD 6 (2014)
Amazon Kindle Fire HD 7 (2014)
Amazon Kindle Fire HDX 7 (2013)
Amazon Kindle Fire HDX 7 (2014)
Amazon Kindle Fire HDX 8.9 (2014)
Asus Google Nexus 7
Huawei MediaPad X1
NVIDIA SHIELD Tablet
Samsung Galaxy Mega 6.3 I9200
Samsung Galaxy Note 8.0
Samsung Galaxy Note LTE 10.1 N8020
Samsung Galaxy Note 10.1 (2014)
Samsung Galaxy Tab Pro 8.4
Sony Xperia Z2 Tablet LTE
Note: The Asus Transformer Pad TF300T is incompatible with Hearthstone. Devices with PowerVR 540/544 GPUs may experience graphical issues. Updating your device to the latest version of your operating system may address these issues. Android 5.0 (Lollipop) and Fire OS 4.5.1 are recommended.
Note that this is just a listing of devices that are verified to run well, less capable devices can probably still run it, but with some lag and crashes. Why does it crash? Well it crashes fairly often on my iPad2 (512 MB RAM) due to memory limitations (you can see device crash logs) if you open the friend's list, but has never crashed on my new iPad Air 2 (2 GB RAM).
TLDR: If you want Hearthstone to run well, and want to buy a tablet, get a device with at least 1 GB RAM.
Note: The list doesn't include any phones - they are releasing for tablets first by end of the year, then both iOS/Android phones early next year.