What happens on Testnet?

[NeuroticFish]

I just noticed that on testnet there's a chain split. Then I noticed something else: there is something strange with the new blocks - they come out way too fast - on both chains.
While I know that testnet is worthless, I am concerned about this test because it looks malicious.

Edit: to make it clear: I would like more info, if anyone can help with that.

[achow101]

Testnet has a low difficulty and a special rule that the difficulty resets to 1 if a block hasn't been mined for 20 minutes. Because of this, testnet miners will game the difficulty system so that the difficulty is almost always 1 so blocks end up being produced extremely quickly. Because blocks are found so quickly on testnet, forks and large chain reorgs tend to occur. This is (probably) normal behavior.

[NeuroticFish]

a special rule that the difficulty resets to 1 if a block hasn't been mined for 20 minutes

This clears it up. Thank you.

[jackg]

@achow I'm guessing this is due to making it much nicer to test the blockchain on test net as it is a lot faster to get a transaction into a block if the blocks are more frequent.

The chain split thing is quite interesting, is that due to the speed of the blocks or something else, have you been able to pick a chain also?