Quote from: RapTarX on Today at 09:35:02 AM

BTW, what's their criteria for not accepting new acceleration request until they find new block?

It seems that they stop accepting new transactions once they reach a certain size of transactions waiting to be mined freely.
Of course, nothing has been mentioned on their website and I don't know the exact amount. I just know that it should happen very rarely. ViaBTC has around 10% of the total hash rate and it's estimated that they mine 1 block in every ~ 100 minutes on average.

Quote from: RapTarX on Today at 09:35:02 AM

Is it because they want some high fee txs to be included in the block they mine? Or just because we have block size limit?

They could accept more transactions, but it seems that they don't allocate the space of each block more than a certain amount to free transactions.