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Testing and Benchmarking Discuss, design, and debate ways to evaluate the performace of he goods out there. |
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06-19-2004, 10:03 AM | #76 |
Thermophile
Join Date: Sep 2002
Location: Melbourne, Australia
Posts: 2,538
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Maybe others could give their experiences, but in dealing with thousands of disk drives in customer installed bases under fairly heavy use, I can honestly say that disk drive reliability has practically fallen through the floor in recent years, and modern SCSI drives are not excepted either.
Now, more so than ever, the three most important words in computing are "backup", "Backup", and "BACKUP!". |
06-20-2004, 04:44 PM | #77 | |
Cooling Savant
Join Date: Oct 2001
Location: Wigan UK
Posts: 929
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Quote:
TIM layer is simulated as 0.1x32x32mm of 10w/m*c material. Might prefer a circular Die simulation. For this Waterloo, additionally, calculates for Parabolic Flux distribution. Edited and corrected. Edit2 : Corrected "Kryotherm" to "Waterloo" Last edited by Les; 06-21-2004 at 05:44 AM. |
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06-20-2004, 05:58 PM | #78 |
Cooling Savant
Join Date: Oct 2001
Location: Wigan UK
Posts: 929
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Oh Woe.
Errors in last post. Will edit and correct. Last edited by Les; 06-20-2004 at 06:09 PM. |
06-20-2004, 06:10 PM | #79 |
Cooling Savant
Join Date: Mar 2003
Location: MO
Posts: 781
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Very interesting.
The amount of drop from adding the IHS seems excessive to me, though. Since a thicker baseplate can be pictured as TIM-less IHS, those graphs imply that most every waterblock could use a thicker base. The first run though of the more-detailed-die-for-Bill model failed. Seems someone left out a single character when scripting the IHS-WB TIM, leaving the block and IHS not actually connected. Simulation stopped when the die hit 1.4e+14 Kelvin (2^47, the highest number it handles). Hey! You pulled off the graphs while I was replying! Now I'm all confused. |
06-20-2004, 06:34 PM | #80 |
Cooling Savant
Join Date: Oct 2001
Location: Wigan UK
Posts: 929
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Having silly problems with my guess of TIM simulant(terminology?).
Hopefully have sorted and chosen 0.1x32x32mm of 10w/m*c material. 10w/m*c material gives an acceptable. C/W(TIM)=0.1c/w for 0.1x10x10mm layer. Was in panicking . Happy with graphs now and posted |
06-20-2004, 07:11 PM | #81 |
Cooling Savant
Join Date: Mar 2003
Location: MO
Posts: 781
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Hmmm, Arctic Silver claims 35 W/(cm^2*K) TIM, yours works out to 10 W/(cm^2*K).
For the IHS-WB, I'm using 20 W/(cm^2*K), based on pH's and Cathar's estimates of 0.07 C/W (which would include the C/W of the silicon). For die-IHS (applied under perfectly controlled conditions) I went with AS's 35 W/(cm^2*K). |
06-20-2004, 07:14 PM | #82 |
Thermophile
Join Date: Sep 2002
Location: Melbourne, Australia
Posts: 2,538
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Only problem I have with graphs is apparant disjuncture from user experience. I would say that every person I've ever heard of removing the IHS has noticed at least some sort of temperature drop, which includes air-cooled heatsinks, having a significantly lower effective value for h than ~20K.
IMO, theoretically the IHS only helps those with aluminium based heatsinks, or for those heatsinks that use a way-too-thin amount of copper material between the core and the fins. In practise, I have not seen anyone report higher temperatures with the IHS removed. |
06-20-2004, 07:32 PM | #83 | |
Cooling Savant
Join Date: Oct 2001
Location: Wigan UK
Posts: 929
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Quote:
However Waterloo possibly underestimates the 1-D Resistance of 10x10mm sections of TIM and Cu.(0.1c/w and ~ 0.026c/w) I take this to be the differences in Resistances extrapolated to infinite h(eff) I am always confused. Edit: Corrected "Kryotherm" to "Waterloo" Last edited by Les; 06-21-2004 at 05:41 AM. |
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06-20-2004, 08:44 PM | #84 | |
Cooling Savant
Join Date: Oct 2001
Location: Wigan UK
Posts: 929
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Quote:
" heff is the effective heat transfer coefficient acting on the surface" be it die, HS baseplate,or IHS. For a given HS these 3 will have different values. Certainly h(bp eff) may be < 20k, and possibly h(IHS eff) may be. However h(die eff) will be above to give a TIMless C/W below 0.5( 1cm sq die) |
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06-29-2004, 02:24 AM | #85 | |
Cooling Savant
Join Date: Oct 2001
Location: Wigan UK
Posts: 929
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Quote:
Am now very unsure about this. Needs further thought. |
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