[ECUPirate]

I'd add a note to ECUPirate (and I missed that apparent exchange with BillA). More small holes doesn't mean less flow resistance. For a given total cross sectional area, you'll see the lowest flow restriction from a single round channel. You can approximate the effect of varying hole size and quantity with equations, but with the twists and turns in a typical setup it's generally nothing more than a good estimate. Qualitatively assessing a design is one thing, quantitatively assessing it is a whole 'nother ball game.

OK. Let me rephrase... I understand that one channel w/ area 'x' would have less resistance than several channels w/ combined area 'x'. That makes perfect sense. However, a single channel may not be the best design for heat dissipation. My question was basically this: If you have a row of say, 8 holes, and you add another row of 8 holes (all holes the same size), would you not increase flow AND lower total resistance in the block?