The danger with parallel is that because flow rate is reduced you need a lot to begin with to avoid it being reduced below the minimum that's needed for the blocks to work effectively. In that pic the flow is split between four blocks (tri-GPU + CPU), I would not want to do that with a single pump.
____GPU___
____GPU___]--Rad--Res----Pump----CPU---[
I would do:
If my awful ascii art makes sense.
I see what you mean about the "neat and tidy" aspect, but you are likely to get hardly any flow through the CPU block with the setup in that photo.
Parallel is fine if there is equal restriction between the possible paths, which is the case with multigpu and in/out at top/bottom, but with a possibly radically different level of restriction through the GPUs vs the CPU you could end up with a tiny amount of flow in the CPU.
Are you saying to go parallel on pumps?
Putting a cpu in parallel with gpu blocks is a bad idea as water will go the path of least resistance and flow through the cpu block will be crap
He's been told this, he's decided to go for aesthetics over functionality.
You want to put the pumps in series for more flow...
Read the link OLDPHART posted.Parallel, series gives more pressure but the same flow. The basis is that once pump A has accelerated the water as much as it can pump B can't then accelerate it the same again, it's the same way push/pull fans boost pressure but don't really increase airflow much unless their beating resistance.
The only way series would give more flow would be if the was a lot of restriction which the isn't going to be with all the blocks in parallel.