Why are radiators for water cooling systems so huge?

[heimdali]

3 minutes ago, Damascus said:

The 7980XE is an 18 core monster that can OC to 5ghz on all cores, stock TDP is meaningless in this circumstance 

Only 18 cores?  I have 24 here, haven´t seen over 650W being drawn from the UPS for the whole machine yet and don´t even need water cooling

 

[Damascus]

4 minutes ago, heimdali said:

Only 18 cores?  I have 24 here, haven´t seen over 650W being drawn from the UPS for the whole machine yet and don´t even need water cooling

What are the cores clocked to and whats the IPC like?  I'm going to assume its somewhere between 1.6 and 3ghz

[heimdali]

10 hours ago, Damascus said:

What are the cores clocked to and whats the IPC like?  I'm going to assume its somewhere between 1.6 and 3ghz

Right, their lowest is 1600 and highest is 2.97 or what it was, and they go turbo a bit over 3.  I could upgrade to x5690s if I could find the parts for that, but that would be more for the fun of it than anything else.  (x5690s require higher performance heatsinks, which are almost impossible to get, and standard parts don´t fit.  Perhaps one day, I´ll find some for a good price ...)

 

What´s IPC?

 

[The Benjamins]

Car radiator operate at a higher efficacy due to the liquid being cooled is hotter. the bigger the liquid to ambient delta the more efficient any radiator is at cooling the liquid.

 

PC loops will have a average of 10-15c delta when cars could have 50+c delta (as you stated) so for a PC loop it might drop liquid temp by 2c from inlet to outlet on a rad which is lets say 200w, when a car radiator can drop the liquid temp by 10c (for example) which would be 1000w. it doesn't mean the radiator is better but its cooling condition is easier.

 

http://www.xtremerigs.net/2015/02/11/radiator-round-2015/1/

[Damascus]

7 hours ago, heimdali said:

What´s IPC?

IPC is instructions per clock - the amount a CPU can do per Cycle.

 

Think of a chip that can do 2 things per clock and and runs 3 times a cycle it can do 6 things every cycle.  A chip that can do 10 things per clock and runs the same 3 cycles it gets 30 things done in the same amount of time.

[heimdali]

2 hours ago, Damascus said:

IPC is instructions per clock - the amount a CPU can do per Cycle.

 

Think of a chip that can do 2 things per clock and and runs 3 times a cycle it can do 6 things every cycle.  A chip that can do 10 things per clock and runs the same 3 cycles it gets 30 things done in the same amount of time.

Oh I have no idea what the IPC rate is.  They are X5675s, so even upgrading to x5690s is questionable.

 

[heimdali]

6 hours ago, The Benjamins said:

Car radiator operate at a higher efficacy due to the liquid being cooled is hotter. the bigger the liquid to ambient delta the more efficient any radiator is at cooling the liquid.

 

PC loops will have a average of 10-15c delta when cars could have 50+c delta (as you stated) so for a PC loop it might drop liquid temp by 2c from inlet to outlet on a rad which is lets say 200w, when a car radiator can drop the liquid temp by 10c (for example) which would be 1000w. it doesn't mean the radiator is better but its cooling condition is easier.

 

http://www.xtremerigs.net/2015/02/11/radiator-round-2015/1/

Wow, someone has already done the kind of testing I had in mind a year ago!  So much to new ideas ...

 

I´m starting to think that the radiator I was using was not very efficient at all.  It never needed to be because the delta between outside air and engine coolant is high enough for it to work anyway.

 

How come that the delta with computers is so low?  Are you saying that the coolant temperature just doesn´t get more than 10--15 above ambient?

 

[The Benjamins]

3 minutes ago, heimdali said:

Wow, someone has already done the kind of testing I had in mind a year ago!  So much to new ideas ...

 

I´m starting to think that the radiator I was using was not very efficient at all.  It never needed to be because the delta between outside air and engine coolant is high enough for it to work anyway.

 

How come that the delta with computers is so low?  Are you saying that the coolant temperature just doesn´t get more than 10--15 above ambient?

 

so most CPU have a high of 80c, so for starters you liquid will never exceed TJMax (most CPUs are around 90c)

 

but to efficiently keep the CPU cool to a ideal 60-70c the liquid temp needs to be a good amount below that. When the liquid temp gets above 35-40c the CPU is no longer being cooled that well.

 

basically the cooler the liquid the more efficiently the blocks can cool the parts, but the cooler the liquid the worse the RADs preform. that is why people use so many RADs.

 

PC have a smaller thermal envelope, a cars coolant temp can go up to 110c on average which means the radiators are more efficient and the blocks can run at higher temps then CPU's

[heimdali]

6 minutes ago, The Benjamins said:

[...]

but to efficiently keep the CPU cool to a ideal 60-70c the liquid temp needs to be a good amount below that. When the liquid temp gets above 35-40c the CPU is no longer being cooled that well.

[...]

Right, I should have thought of that.  And at a given ambient temperature, you can only keep the coolant temperature low enough by either using more airflow, which might get noisy, or by using more surface area which equates to more airflow without the noise.

 

Without all the pre-made stuff for water cooling you can get nowadays, it would probably be easy to put something together that doesn´t provide enough cooling ...

I begin to feel tempted to do some water cooling again.