You'll now have to fork out for an additional subscription if you want to watch 4K content on Prime Video

Amazon is raising the price of its ad-free Prime Video subscription and locking 4K UHD streaming behind this new tier. Starting April 10 for US customers, a rebranded Prime Video Ultra subscription will cost $5 per month, up from $3 per month.

For that extra $2, you get a download capacity increase from 25 to 100, and you can now run five streams concurrently instead of three. Whether those "Ultra" upgrades are worth the $24 annual hike will probably depend on how many boxsets you like to plough through on a long flight, or how many devices are using your Prime Video account.

The changes are most galling for Prime members who automatically qualify for Prime Video with ads through their membership, as Amazon has decided to remove 4K streaming from the standard tier. That means that, despite already paying $15 per month or $139 per year for ...