It doesn't work that way. It didn't take that long to find a specific block, it took that long to find any block. Every time someone else finds a block, we start looking for a new block based on what they found. That's why we call that 12 hours a round, not a block.
So every time you see "stratum detected a new block" in the miner log would indicate that the hashing power is being spent on solving a block rather than looking for a new one? Unless someone solves that block first. But if you don't see a new block detected for a long while, the hashing power is being spent finding a new one?
How is hashing power divided between looking for new blocks vs solving, is there a ratio set by the pool operator depending on how many active blocks have been found?
-noob.
When you see "stratum detected a new block" it means that someone somewhere in the world found a solution for the current block and that a new block is now being worked on. Solving is looking for new blocks. Different names for the same thing.
The thing is that there is more than one right solution for any given block. All the pools and solo people use different inputs than every one else in hopes that their input will find the desired output. Say your hashrate is 5 Gh/s, that means you are checking 5 million different inputs every second looking for the one output that will complete the block.