I don't think that's already known. Playkey will probably still need to release the specs.
In the Whitepaper they talk about miners, but it's not defined as far as I know.

If there any plan to organize tournaments on play key with money or token rewards to bring more gamers to the platform?

Did anyone find the subscription fee? I found a price of about $8 a month in the whitepaper.

When purchased using a pay-monthly scheme over a period of 3 years, the price for per month for that same PC is $83. A monthly cloud subscription fee can be one tenth of that price.

Playstation Now costs $20 a month for a library of over 500 PS4 and PS3 games. The subscription fee for PlayKey is lower, but players have to buy the game keys as well.

Playkey provides a list of games supported by the application, and of their installation files. A miner decides which games he wants to rent out on his computer, and installs them. Or he selects automatic mode, whereby Playkey autonomously analyzes demand and manages the games on his computer to maximize his profit and, accordingly, that of the service.

Game keys are purchased by users and they are activated the same way in games, the only difference being that the game is launched at the miner’s computer. Keys can be purchased either on the Playkey website or in any other way at the discretion of the player.

It is a trade-off.

PlayKey:

+ $8 a month
+ supports PC games
+ can play on low-end PC, iMac, laptop, tablets, smartphones, Smart TV
- have to buy game license (games bought in a bundle less than $1 a piece, but the latest AAA games can cost $50+)
- can you share or transfer your game license on PlayKey to your own PC?
- no PlayStation games

PlayStation Now:

+ includes 500+ PS4 and PS3 games
- $20 a month
- no PC games
- can only play on PC and PS4