Re: What does a node do?

So do the SPV miners still get the transaction money even though they haven't verified? What happens when it becomes too difficult to find new blocks, will it be impossible to transfer Bitcoins?

As long as the previous block follows the network rules and it doesn't get orphaned. SPV mining deducts the time used for verifying. They assume that the longest chain is valid.*

*Mining pool runs a full node but due to how SPV works, they will continue to mine on invalid chain.

Does it verification use a lot of CPU power? I used to mine llitcoin with a very low end CPU and did not see any problem?

No. The proporgation of block and verification does take sometime. Those miners who SPV mines listens on the other pools for block changes. They then check the coinbase for conflicting transactions and use the hashes to generate a new block header to mine. This essentially means that the SPV miner does not verify the block and trust that the other miner follows the network rules(eg. Not putting a 10k BTC block reward). If the miner makes a mistake and mines a block which doesn't follow the network rules, the SPV miners will continue to build on that chain and thus lose all the block rewards since they are mined on the wrong fork.

SPV mining can reduce the chances of getting the block orphaned.