[Joe]

ok fair enough, then tell me this:

Even if it makes HARDLY a difference, WHY still do it? You are building a cooling system to cool yer CPU better! Why handicap it by bad engineering? Yes it may be a small difference, but it doesnt matter, you are still putting a heat producing device before the block.

There is NO "the warm water will burn out my pump" deal. ( most of these are fish tank pumps, they are made to move warm water)