Flow rate and head pressure

[valve]

I've read about the differences between flow rate and head pressure. I don't understand, however, how a pump can have a higher flow rate but a lower head. If you pump a water stream faster, it is going to overcome more resistance (thus a higher head value)...right? 

Also, is a 3.9 meters head enough for a CPU hard tubed custom loop?

[Enderman]

If the pump has an outlet that is 2x larger and can move 2x more water aka double the flow rate, the head pressure remains the same because the flow rate divided by the cross sectional area doesn't change.

 

If the pump has to push double the flow rate through the same area then yes the head pressure would need to be higher.

 

It all depends on the amount of frictional resistance of the pump.

 

Yes 3.9m is more than enough for any loop.

[valve]

10 minutes ago, Enderman said:

If the pump has an outlet that is 2x larger and can move 2x more water aka double the flow rate, the head pressure remains the same because the flow rate divided by the cross sectional area doesn't change.

  

If the pump has to push double the flow rate through the same area then yes the head pressure would need to be higher.

  

It all depends on the amount of frictional resistance of the pump.

ok thanks that makes sense

10 minutes ago, Enderman said:

Yes 3.9m is more than enough for any loop.

Then what are 7meters head ddc pumps used for? 

[Drak3]

22 minutes ago, valve said:

Then what are 7meters head ddc pumps used for? 

Those are useful for systems running multiple waterblocks on a loop. Think watercooling multiple GPUs, VRM, CPU, etc. at the same time.

[Enderman]

25 minutes ago, valve said:

ok thanks that makes sense

Then what are 7meters head ddc pumps used for? 

Running them slower, or stuff with like 20 waterblocks.

[valve]

5 hours ago, Drak3 said:

Those are useful for systems running multiple waterblocks on a loop. Think watercooling multiple GPUs, VRM, CPU, etc. at the same time.

 

5 hours ago, Enderman said:

Running them slower, or stuff with like 20 waterblocks.

So I wouldn't need a 7meters head even for a CPU GPU custom loop system (two waterblocks)?

[Drak3]

Just now, valve said:

 

So I wouldn't need a 7meters head even for a CPU GPU custom loop system (two waterblocks)?

No, the D5 is more than enough.

[Enderman]

4 hours ago, valve said:

 

So I wouldn't need a 7meters head even for a CPU GPU custom loop system (two waterblocks)?

Maybe if you had 7 GPU blocks and two CPU blocks and then 5 radiators.

Or also if you had ram and VRM waterblocks instead of tons of GPU blocks.