First thing I notice is:
phpBB Created this page in 0.970943 seconds : 14 queries executed : GZIP compression disabled : Debug Mode
now my board, running on a FAR lesser machine....(at least from what they claim...
phpBB Created this page in 0.194275 seconds : 17 queries executed : GZIP compression enabled
Any host that offers "unlimited bandwidth" is likely at least to some degree a fraud. No one can deliver "unlimited bandwidth" so they will limit you in some other way. In this case it seems through CPU usage.
If a machine like you are on is taking that long to make the pages and make the DB querries, there is a load problem to begin with....
I would suggest finding a new host...