4 ms·
When you're arguing over a 110 watt difference, 50 watts lost as heat in the PSU is not insignificant and certainly enough to skew a test.
by msimpson 10y ago
When you're arguing over a 110 watt difference, 50 watts lost as heat in the PSU is not insignificant and certainly enough to skew a test.
- ksk 10y agoThe author is comparing how off the numbers are from the stated specs, not establishing the accuracy of individual figures. If the extraneous power-draw is reasonably constant, it can provide an interesting comparison.
- msimpson 10y agoThe author is comparing how off overall power consumption is from the stated thermal design power under a sustained, heavy load; which is not what TDP is intended to measure ... "TDP is not the maximum power that the processor can dissipate." -- Intel Keep in mind that TDP is only a target number for typical use, not mprime. Not to mention Intel and AMD define it differently, see: http://www.silentpcreview.com/article169-page3.html http://www.silentpcreview.com/article169-page3.html "Intel is listing TDP numbers that are significantly lower than the actual maximum power draw of their CPUs." That article is THIRTEEN YEARS OLD!
- ksk 10y agoYes, so the obvious point for the reader to glean is that Intel is sneaky about using different ways of calculating TDP for different products. Why they would do that is anyones guess. Obviously they wouldn't want to give out false information to system builders who might end up with underpowered PSUs and overheating CPUs.
- msimpson 10y agoSo if TDP is a measure, given in wattage, of thermal dissipation of a CPU under a typical load. Why can't I simply assume double that value for a CPU's actual power consumption under heavy load? I mean, using that logic the max power consumption for the same six core processor Atwood tested would be around 280 watts. A number only 40 watts higher than his for heavy load. Too bad I used "false information" to reach such a usable number. Now if the actual power consumption was double that, I'd definitely be berating Intel. But alas, no.
- ksk 10y agoPractically, sure, you pretty much have to do whatever it takes to get it working. But its not like we're talking about trade secrets here. They simply have to release a coherent definition of what they consider a typical load. I get your point, but nothing wrong in drawing attention to the specs being incomplete to the point of being useless.
- msimpson 10y ago> They simply have to release a coherent definition of what they consider a typical load. Have fun getting AMD and Intel to agree on something. > I get your point, but nothing wrong in drawing attention to the specs being incomplete to the point of being useless. Vague or averaged is not useless.
- ksk 10y agoWhat does Intel documenting their own specs have to do with AMD?
- msimpson 10y agoTDP is used by multiple manufacturers, so getting a "coherent definition" is going to take work. If you want to understand more about the thermal specs from only Intel. You can read their thermal guide: http://www.intel.com/content/dam/www/public/us/en/documents/guides/xeon-e5-v3-thermal-guide.pdf http://www.intel.com/content/dam/www/public/us/en/documents/...
- ksk 10y agoSorry, I don't understand your point. Each vendor already defines it in their own way. The point of the article is that without proper guidance you end up guessing. I'm afraid the guide you linked to doesn't help much. Intel confusingly tells us "TDP: Thermal solution should be designed to dissipate this target power level. TDP is not the maximum power that the processor can dissipate." So according to Intel [1] - "The best way to measure a server’s power consumption is the power meter, an inexpensive tool that is plugged into the wall, and then your device, like a server, can be plugged into the power meter. The meter displays the wattage drawn "at the wall" and allows you to analyze the power consumption under a variety of different utilization levels.". Strange. I was looking up docs on AMD. They seem[2] to kinda get it: "To allow optimal reliability of the AMD Opteron and AMD Athlon 64 processor-based systems, the thermal and cooling solution should dissipate heat from a processor operating at its maximum thermal power.". I could find some old docs[3] that did give the maximum power, but can't seem to find any on their recent CPUs. [1] http://www.intel.com/content/dam/doc/white-paper/resources-xeon-measuring-processor-power-paper.pdf http://www.intel.com/content/dam/doc/white-paper/resources-x... [2] ftp://ftp.sgi.com/public/Technical%20Support/Pdf%20files/AMD/26633_5649.pdf [3] http://hackipedia.org/Platform/x86/AMD/AMD%20Thermal,%20Mechanical,%20and%20Chassis%20Cooling%20Design%20Guide%20(January%202002).pdf http://hackipedia.org/Platform/x86/AMD/AMD%20Thermal,%20Mech...
- lightedman 10y agoThat 50 watts only happens under a fully-loaded PSU scenario. 500w PSU at full load would deliver at 80+ rating ~400w. That same PSU just rolling barely enough equipment to keep a processor fully fed might draw 300w from the PSU, of which maybe 20w of that is wasted. This is basic PSU and power supply principle.
- msimpson 10y agoAs I said, "variables that can amount to TENS of watts."