OK, like suggested I turned the H50 radiator around 180 degrees...now temps after startup are about 3-5 degrees higher than they were: on idle. I'm guessing one of the probable reasons for this is that the pipes now go up and around instead of down, meaning that water flow is decreased. Of course, it could always be the room temp: I'll get a new thermometer to check within the next few days.
Regardless, 35 degrees as opposed to around 30 on IDLE isn't brilliant. And my room doesn't feel nearly that, at all (I'm dreading summer).
ok 35 degrees really isnt much to worry about tbh, but the reason the temps are higher is heat rises, and even in cases with vents at the top of the case you will still get a hot point at the top of the case where the hot air isnt being ejected out of the case fast enough (good example of this is the 700/800D). by rotating the pipes to the top, youve just put them in the hot point/zone hence the temperature increase, so this is kind of personal preference:
1) Have 5 degrees more and have it look neat
2) have it cooler and put up with it not looking quite right
