3 blocks a pump and a pizza joint.
 

Ok. Well no pizza anyway. But is a eheim 1048 sufficient enough for 3 blocks ie. CPU, northbridge, vid. I'm thinking of cooling all three and would hate to have to step up to a 1250 just yet.

Yes.

A 1250 might do a little better, but a 1048 is hardly underpowered. Don't waste your money yet.

just run it with the 1048, and see how your temps are. If you aren't satisfied, upgrade to a bigger pump

once you spend that 1st dollar on WC stuff, the dollars just start to fly out the window, and you don't even care! :)

I wish. So far the dollars are flying out of my head but not to much out the window yet.

Yes, the 1048 is sufficient for what you're planning. My experience is that the radiator can be a very limiting factor, so I've ordered a heater core to replace my mini-rad.

If you're really paranoid about flow you can run the three components being cooled (NB, GPU, CPU) in parallel, i.e. PUMP > RADIATOR > Y-FITTING --path 1:cpu...y-fitting --path 2: y-fitting (--path 2a...gpu --path 2b...nb--)...y-fitting > y-fitting > (airtrap) > PUMP.

However, if you're running in a mid-tower, the tubing can be a bit difficult to route without kinks and the like, it's going to take a hella lotta hose clamps, and there are plenty more places to spring a leak, etc. Ultimately, I doubt you'll see any tangible increase in performance, when compared with running CPU > GPU > NB in series.

An alternative is to only have two paths, i.e. PUMP > RADIATOR > Y-FITTING --path 1:cpu --path 2:gpu...nb > Y-FITTING > (airtrap) > PUMP.

Jaani: Y-fittings cause a pressure drop which would *reduce* the flow. Running in parrallel would not seem like a good idea to me. Also, most of the time, running in a serial arrangement perfomrs better than running in parallel.

Just remember, water will take the path of least resistance, so make sure if you run them parallel, that you don't have any deadspots.