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Exceeding maximum absolute voltage
By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM
chips be exceeded? I don't intend to do it, but I have a motherboard that lets the memoy voltage be set as high as 2.839V, and it's maker says that's OK, although they won't guarantee against damage. |
#2
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Exceeding maximum absolute voltage
On Fri, 17 Sep 2010 15:59:03 -0700 (PDT), "larry moe 'n curly"
wrote: By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM chips be exceeded? Nothing. That would be why they call it "absolute maximum" eh? Maybe you get lucky and nothing bad *apparently* happens, maybe it goes Pffft!, maybe it just slowly corrupts your files. I don't intend to do it, but I have a motherboard that lets the memoy voltage be set as high as 2.839V, and it's maker says that's OK, although they won't guarantee against damage. The motherboard manufacturer or the memory manufacturer? An engineering rep or some guy in an off-shore call center? -- Rich Webb Norfolk, VA |
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Exceeding maximum absolute voltage
larry moe 'n curly wrote:
By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM chips be exceeded? I don't intend to do it, but I have a motherboard that lets the memoy voltage be set as high as 2.839V, and it's maker says that's OK, although they won't guarantee against damage. One way to get that info, is if the manufacturer writes up an ISSCC (International Solid State Circuits Conference) paper. Sometimes, if they've done a new semiconductor process, the details will be given in the paper, including the "real" absolute max (i.e. the value that killed the device in the lab, something akin to breakdown voltage). The only time I read and compared such a value using a paper like that, it was about 200mV above the datasheet value, which isn't much margin at all (and that was for a non-Intel processor). Or, you can look in an enthusiast forum, and see what they're up to. Some Micron D9 tested at 2.51V. Try to find a thread where they burned some up :-) http://www.xtremesystems.org/forums/...d.php?t=121284 Paul |
#4
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Exceeding maximum absolute voltage
Rich Webb wrote: On Fri, 17 Sep 2010 15:59:03 -0700 (PDT), "larry moe 'n curly" wrote: By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM chips be exceeded? Nothing. That would be why they call it "absolute maximum" eh? Maybe you get lucky and nothing bad *apparently* happens, maybe it goes Pffft!, maybe it just slowly corrupts your files. I don't intend to do it, but I have a motherboard that lets the memory voltage be set as high as 2.839V, and it's maker says that's OK, although they won't guarantee against damage. The motherboard manufacturer or the memory manufacturer? An engineering rep or some guy in an off-shore call center? All the RAM chip makers and engineers who used to work for local chip companies all agreed with you -- emphatically. It was the motherboard maker, BioStar that said it was OK to exceed 2.3V, even though they wouldn't guarantee against damage to the memory, and they said the memory would very likely burn up at 2.4V. I don't think any of those people at BioStar knew anything -- too pretentious and authoritarian. |
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Exceeding maximum absolute voltage
On Sep 17, 8:18*pm, Paul wrote:
larry moe 'n curly wrote: By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM chips be exceeded? *I don't intend to do it, but I have a motherboard that lets the memoy voltage be set as high as 2.839V, and it's maker says that's OK, although they won't guarantee against damage. One way to get that info, is if the manufacturer writes up an ISSCC (International Solid State Circuits Conference) paper. Sometimes, if they've done a new semiconductor process, the details will be given in the paper, including the "real" absolute max (i.e. the value that killed the device in the lab, something akin to breakdown voltage). The only time I read and compared such a value using a paper like that, it was about 200mV above the datasheet value, which isn't much margin at all (and that was for a non-Intel processor). Or, you can look in an enthusiast forum, and see what they're up to. Some Micron D9 tested at 2.51V. Try to find a thread where they burned some up :-) http://www.xtremesystems.org/forums/...d.php?t=121284 * * Paul The fine geometry MOS these days is nearly like eeprom of the dark ages. There is a threshold shift of the fets as they are clocked. My recollection is threshold voltages get larger over time, but don't quote me. The shift is incorporated into the spice models (or should be). [If the threshold increases, then the weak model.] If you increase the voltage, you probably won't get the 10 year life for which the process is probably specd. Stick with Asus or Gigabyte. I'm leery of 2nd tier mobos. |
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Exceeding maximum absolute voltage
On Fri, 17 Sep 2010 15:59:03 -0700 (PDT), "larry moe 'n curly"
wrote: By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM chips be exceeded? I don't intend to do it, but I have a motherboard that lets the memoy voltage be set as high as 2.839V, and it's maker says that's OK, although they won't guarantee against damage. If they won't guarantee it, then they know it is too high. The numbers you cite are almost 20% higher than spec. |
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Exceeding maximum absolute voltage
On Fri, 17 Sep 2010 15:59:03 -0700, larry moe 'n curly wrote:
By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM ^^^^^^^^^^^^^^^^ chips be exceeded? I don't intend to do it, but I have a motherboard that lets the memoy voltage be set as high as 2.839V, and it's maker says that's OK, although they won't guarantee against damage. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Read your own question again, with emphasis as shown. In other words, pretty much zero, if you want it to operate as advertised. Good Luck! Rich |
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Exceeding maximum absolute voltage
On Sep 17, 6:59*pm, "larry moe 'n curly"
wrote: By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM chips be exceeded? *I don't intend to do it, but I have a motherboard that lets the memoy voltage be set as high as 2.839V, and it's maker says that's OK, although they won't guarantee against damage. The world may never know: http://www.youtube.com/watch?v=Jhjb4...t=1& index=49 |
#9
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Exceeding maximum absolute voltage
Rich Grise wrote: On Fri, 17 Sep 2010 15:59:03 -0700, larry moe 'n curly wrote: By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM ^^^^^^^^^^^^^^^^ chips be exceeded? I don't intend to do it, but I have a motherboard that lets the memoy voltage be set as high as 2.839V, and it's maker says that's OK, although they won't guarantee against damage. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Read your own question again, with emphasis as shown. In other words, pretty much zero, if you want it to operate as advertised. The motherboard manufacturer, BioStar, wouldn't guarantee against damage even if I never exceeded the chip maker's maximum absolute of 2.3V, nor would they guarantee that the voltage applied to the memory would never go above that by itself, such as because of a glitch. |
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Exceeding maximum absolute voltage
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