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pHaestus · 05-26-2002, 12:02 PM

Better move C/W way down (off?) that list, as the whole power issue rears its head again (with a vengeance now). Bet you can guess I was going to say that after reading that thread? There are always tradeoffs; best plan is to simply address them.

There are some advantages and disadvantages of both the simulators you propose and actual CPUs:

Regarding testing with actual processors, the advantage is that you actually have a "realistic" load for the waterblock to deal with, with its dimensions and material and heat release pattern being consistent. Disadvantages are myriad: You don't actually know the heat load, you have difficulties in measuring the temperature with any accuracy, you have to contend with secondary heat losses and cooling pathways that complicate precise determination of a waterblock's performance.

Wait though that last one is REAL cooling that is relevant. Processor temperatures can be collected with a reasonable degree of accuracy with a carefully calibrated diode reader (no mobos), and the processor heat load can hopefully be ballparked better than currently done (how well? I hope AMD will respond to my e-mails). This is where I am headed right now, as there are issues with the simulators (and cost) that I can't surmount at the moment. Prevailing wisdom for testing is to crank the voltage and MHz, but if I can get more reliable heat load numbers from AMD for 1.75V and 1200MHz than I can for 2.0V and 1400MHz then shouldn't I go with the speed that improves certainty in heat input? Comments? I am also guessing that perhaps someone with a good simulator might be willing to help me check my W estimates by comparison with their known power inputs (pokes Bill with a stick).

Ok onto the simulators. I don't think that the W that is coming from most of these is any better than the W coming from radiate (or similar) for CPUs; it just looks more scientifically sound and so people don't question it. Look at that o/cers au thread for my diode reader comparison with JoeC's simulator. The only conclusion is that you really aren't any more certain of the power input with a resistor type simulator than you are with a CPU so the big advantage is the use of an embedded thermocouple over a CPU diode (not that this isn't a good thing).

Gotta think carefully about what you want to know and when to cut your losses. What were we even looking at again? Which block is "best"? I forget...

05-26-2002, 12:02 PM	#50
pHaestus Big Player Making Big Money Join Date: Aug 2001 Location: irc.lostgeek.com #procooling.com Posts: 4,782	Better move C/W way down (off?) that list, as the whole power issue rears its head again (with a vengeance now). Bet you can guess I was going to say that after reading that thread? There are always tradeoffs; best plan is to simply address them. There are some advantages and disadvantages of both the simulators you propose and actual CPUs: Regarding testing with actual processors, the advantage is that you actually have a "realistic" load for the waterblock to deal with, with its dimensions and material and heat release pattern being consistent. Disadvantages are myriad: You don't actually know the heat load, you have difficulties in measuring the temperature with any accuracy, you have to contend with secondary heat losses and cooling pathways that complicate precise determination of a waterblock's performance. Wait though that last one is REAL cooling that is relevant. Processor temperatures can be collected with a reasonable degree of accuracy with a carefully calibrated diode reader (no mobos), and the processor heat load can hopefully be ballparked better than currently done (how well? I hope AMD will respond to my e-mails). This is where I am headed right now, as there are issues with the simulators (and cost) that I can't surmount at the moment. Prevailing wisdom for testing is to crank the voltage and MHz, but if I can get more reliable heat load numbers from AMD for 1.75V and 1200MHz than I can for 2.0V and 1400MHz then shouldn't I go with the speed that improves certainty in heat input? Comments? I am also guessing that perhaps someone with a good simulator might be willing to help me check my W estimates by comparison with their known power inputs (pokes Bill with a stick). Ok onto the simulators. I don't think that the W that is coming from most of these is any better than the W coming from radiate (or similar) for CPUs; it just looks more scientifically sound and so people don't question it. Look at that o/cers au thread for my diode reader comparison with JoeC's simulator. The only conclusion is that you really aren't any more certain of the power input with a resistor type simulator than you are with a CPU so the big advantage is the use of an embedded thermocouple over a CPU diode (not that this isn't a good thing). Gotta think carefully about what you want to know and when to cut your losses. What were we even looking at again? Which block is "best"? I forget...