re: me: In Intel's case, for the quad core X5300 series 120w (145w max) Xeons, Intel states categorically that a heatsink designed to allow Tcase to reach 70C when dissipating 120w WILL result in "noticeable performance loss due to increased TCC activation [thermal throttling]." They state this is true even if the actual Tcase temp doesn't come close to 70C!you: <In this statement, you are only referring to the Thermal Profile B solution,
which according to the spec is a reduced specification meant for 1U form factors.
It's meant to give the designers a means of cooling the X-series Xeon in volumetrically
constrained spaces, where otherwise, the choice would be to drop down to E-series parts.>You are just obfuscating here. I am setting out to prove that all Clovertowns NEED to have a HSF that keeps the temperature at 63 and below or they will suffer "noticeable performance loss" -- Intel's words, not mine. The name Intel gives to the 70C solution is irrelevant.
The spec also notes that servers will maintain the 63C degree Tcase of Thermal Profile A due to TCC activation, so you can extrapolate that the Thermal Profile B heat sink is really only dissipating 90W
...yea, and they will have "noticeable performance loss"
According to this spec, Intel's Thermal Profile B Psi(ca) guideline is 0.249 C/W. ... This makes Xeon actually slightly easier to cool than Opteron.
...but we've established that Thermal Profile B results in noticeable performance degradation. Don't even go there! No AMD solutions have any performance degradation whatsoever.
Only the standard X-series Thermal Profile A Psi(ca) is 0.190 C/W. This makes Xeon actually slightly easier to cool than Opteron.
I did my own calculations of required HSF performance in °C/W because AMD and Intel might have different assumptions about the temp inside the server case. Turns out I was right -- Intel uses 40°C and AMD uses 38°C. There's no magic here, but its clear that keeping Tc below 63 to avoid Intel thermal throttling is a lot more difficult than keeping it below 67-72°C. So comparing AMD's SE series parts to Intel's X series parts, AMD is easier to cool.
Actually, my claim is that Pete has invented a term that he calls TDPmax, but it doesn't relate to anything in the Intel specs.
Yes, Intel's TDPmax of 145w for X-series Xeons is not the same as Pete's.
Petz |
