No, the request wont consume 2000ms of CPU time if it's blocking. It will prevent the thread from doing other work which may be bad, but the CPU itself does not have to spend all 1700ms on that thread. At least my CPU doesn't use 100% of a core while waiting for a network package from the database server.
Should have phrased it as "the blocking wait will consume resources (keep a thread busy) for 1700ms whereas the async one will not." Hard to stay both accurate and extremely simple when talking about concurrency.
