3 ms·

> The result of that 3.0 GHz overclock? A marginally-improved Geekbench 6 score of 1662, versus 1507 with no OC. To achieve that 10% speedup, it ate up about 20

> The result of that 3.0 GHz overclock? A marginally-improved Geekbench 6 score of 1662, versus 1507 with no OC. To achieve that 10% speedup, it ate up about 20% more power, so efficiency-wise, it's not worth it. What effect would running an overclock like this permanently have on longevity? Is it even worth thinking about "longevity" of chips? Obviously stability suffers but for example... how much? Author was able to get a Geekbench 6 benchmark to pass. If they tried 100 times, would it be expected that a non-zero amount would fail?

techwiz137 3y ago
Of course! These are like BGA or something similar, the solder will crack after some number of on/off/cool/heat cycles. If voltage is raised we enter the realm of electromigration, though not sure how relevant it is for such a minuscule OC. As for stability, yes. If the voltage is not sufficient there will be stability issues which will require further raising it, thus raising temps and requiring more power which you can't be sure if you could deliver. And then of course electromigration.
- 0x457 3y ago
  > Of course! These are like BGA or something similar, the solder will crack after some number of on/off/cool/heat cycles. This was mostly happening during the transition to lead-free solder. Today, component should fail earlier than BGA.
sweetjuly 3y ago
Unfortunately, most of the useful data you want about wearout is locked behind tech NDAs so nobody will be able to offer specifics here. But in general, the way you tend to end up with wearout is through electron migration ("electron wind") which is damage to interconnects from electrons slamming into metal atoms over and over and slowly ripping apart the wires. Modeling electron migration correctly is really hard, but (from memory) a general relationship is that voltage linearly increases failure rate and temperature exponentially increases it. The constants for these models are determined empirically and, of course, are NDA'd. In general, I wouldn't worry about it. The MTTF for semiconductors is already very high even under awful temperatures 100+ C, and so as long as you cool it properly you'll be fine. > would it be expected that a non-zero amount would fail? The failures you describe here are going to be due to setup time violations. These issues shouldn't be transient (assuming identical temperature and voltage) since the performance characteristics of an individual device don't really change over time. Of course, the issues can seem transient as the failures may not actually always cause noticeable corruption (maybe you generate a wrong FPU result but that specific path is only exercised under rare uarch conditions). So, it's a non-answer, but: yes and no. Maybe your chip is perfectly okay and never has any violations at the parameters you selected. Maybe it does. Neither you (nor in fact the manufacturer, though they do have a better chance since they know the process/design) can ever really be sure--all that's left is empirical burn in testing and hoping for the best :)
- magicalhippo 3y ago
  I can't find the references right now, but I recall reading that longevity of microcontrollers and similar could also be somewhat accurately modeled by the Arrhenius equation[1], meaning a 10C increase in operating temperature would result in roughly half the expected lifetime. [1]: https://en.wikipedia.org/wiki/Arrhenius_equation https://en.wikipedia.org/wiki/Arrhenius_equation
  - sweetjuly 3y ago
    I believe you might be thinking of Black's equation? [1]. It's one equation which attempts to model the failure rate due to electron migration. It isn't a physical model but it seems to, with the right constants, fit reasonably well. The 10C=>halving life time is going to depend on the constants though. [1] https://en.wikipedia.org/wiki/Black's_equation https://en.wikipedia.org/wiki/Black's_equation
    - magicalhippo 3y ago
      Ah, must be. Though it wasn't mentioned by name in the source[1] I found earlier the equation seems to match. Instead they attribute it to Arrhenius, but I guess Black's equation is a special case. [1]: https://www.ti.com/lit/an/snva509a/snva509a.pdf https://www.ti.com/lit/an/snva509a/snva509a.pdf
mafuyu 3y ago
From what I remember from school, the extremely rough rule of thumb, specifically for thermal effects on the silicon itself, is that +10C will halve the lifespan of the chip. When you try to push a chip with an OC, the power/perf gets highly nonlinear, so you end up making tradeoffs here. Chip vendors like Intel and AMD do a lot of testing and validation to pick power curves that will meet the warranty specs of the chip, but they do have some wiggle room. There’s a whole bunch of other failure modes that aren’t captured by the 10C rule. It’s more for estimating chip failure due to things like electromigration. You can observe this if you run a desktop CPU overclocked for many years. I had a 2600k that I had to keep bumping the OC down on, and jt eventually bit the dust after a decade.
- rodgerd 3y ago
  I once attended a talk by one of the people at Weta Digital about how they ran their datacentres; they worked out that they could save six figure sums per month by running their aircon lower and blades hotter; HP were prepared to keep the blades in warranty for a three degree bump but no more.
latchkey 3y ago
My experience with running GPUs is that overclocking tends to go with undervolting and it has zero impact on longevity of the chips themselves. Other components like power supplies, with consumable or hand made things, like hand soldered components, are what end up failing. We had cards in the worst of the worst environments and they ran fine for years on end.
- bayindirh 3y ago
  I'd not be so sure, actually. Because we have seen other processors on the systems, like RAID or Ethernet cards go "insane" after some years. No overheat, no physical stress, nothing. Normal if a bit too much (HPC) work. Reboot the system, device just disappears, never to be never seen again. It generally starts after ~6 year mark. Sometimes device starts to corrupt things silently, but not always. However they too disappear after some time. Oh, sometimes GPUs do that, too.
  - latchkey 3y ago
    The point being that you don't know which component on the board failed. If you look at the GPU chip itself, it might be just fine and it was just a capacitor that blew.
    - bayindirh 3y ago
      The GPUs we change arrive on a large board which hosts multiple GPUs with SXM interface. GPU itself arrives with its heat sink only, and we only change the GPU itself. Board is never replaced. Same for the RAID card. The processor has a couple of failure modes (no cache or no card), both directly related to RAID processor itself. Again same for the Ethernet cards we fry. They lose their MAC addresses, all pointing to in silica problems.
      - latchkey 3y ago
        Good point. I've also heard that there are fairly high rate of failures with high end nvidia stuff. I wonder why that is.

techwiz137 3y ago

Of course! These are like BGA or something similar, the solder will crack after some number of on/off/cool/heat cycles. If voltage is raised we enter the realm of electromigration, though not sure how relevant it is for such a minuscule OC. As for stability, yes. If the voltage is not sufficient there will be stability issues which will require further raising it, thus raising temps and requiring more power which you can't be sure if you could deliver. And then of course electromigration.

0x457 3y ago
> Of course! These are like BGA or something similar, the solder will crack after some number of on/off/cool/heat cycles. This was mostly happening during the transition to lead-free solder. Today, component should fail earlier than BGA.

sweetjuly 3y ago

Unfortunately, most of the useful data you want about wearout is locked behind tech NDAs so nobody will be able to offer specifics here. But in general, the way you tend to end up with wearout is through electron migration ("electron wind") which is damage to interconnects from electrons slamming into metal atoms over and over and slowly ripping apart the wires. Modeling electron migration correctly is really hard, but (from memory) a general relationship is that voltage linearly increases failure rate and temperature exponentially increases it. The constants for these models are determined empirically and, of course, are NDA'd. In general, I wouldn't worry about it. The MTTF for semiconductors is already very high even under awful temperatures 100+ C, and so as long as you cool it properly you'll be fine. > would it be expected that a non-zero amount would fail? The failures you describe here are going to be due to setup time violations. These issues shouldn't be transient (assuming identical temperature and voltage) since the performance characteristics of an individual device don't really change over time. Of course, the issues can seem transient as the failures may not actually always cause noticeable corruption (maybe you generate a wrong FPU result but that specific path is only exercised under rare uarch conditions). So, it's a non-answer, but: yes and no. Maybe your chip is perfectly okay and never has any violations at the parameters you selected. Maybe it does. Neither you (nor in fact the manufacturer, though they do have a better chance since they know the process/design) can ever really be sure--all that's left is empirical burn in testing and hoping for the best :)

magicalhippo 3y ago
I can't find the references right now, but I recall reading that longevity of microcontrollers and similar could also be somewhat accurately modeled by the Arrhenius equation[1], meaning a 10C increase in operating temperature would result in roughly half the expected lifetime. [1]: https://en.wikipedia.org/wiki/Arrhenius_equation https://en.wikipedia.org/wiki/Arrhenius_equation
- sweetjuly 3y ago
  I believe you might be thinking of Black's equation? [1]. It's one equation which attempts to model the failure rate due to electron migration. It isn't a physical model but it seems to, with the right constants, fit reasonably well. The 10C=>halving life time is going to depend on the constants though. [1] https://en.wikipedia.org/wiki/Black's_equation https://en.wikipedia.org/wiki/Black's_equation
  - magicalhippo 3y ago
    Ah, must be. Though it wasn't mentioned by name in the source[1] I found earlier the equation seems to match. Instead they attribute it to Arrhenius, but I guess Black's equation is a special case. [1]: https://www.ti.com/lit/an/snva509a/snva509a.pdf https://www.ti.com/lit/an/snva509a/snva509a.pdf

mafuyu 3y ago

From what I remember from school, the extremely rough rule of thumb, specifically for thermal effects on the silicon itself, is that +10C will halve the lifespan of the chip. When you try to push a chip with an OC, the power/perf gets highly nonlinear, so you end up making tradeoffs here. Chip vendors like Intel and AMD do a lot of testing and validation to pick power curves that will meet the warranty specs of the chip, but they do have some wiggle room. There’s a whole bunch of other failure modes that aren’t captured by the 10C rule. It’s more for estimating chip failure due to things like electromigration. You can observe this if you run a desktop CPU overclocked for many years. I had a 2600k that I had to keep bumping the OC down on, and jt eventually bit the dust after a decade.

rodgerd 3y ago
I once attended a talk by one of the people at Weta Digital about how they ran their datacentres; they worked out that they could save six figure sums per month by running their aircon lower and blades hotter; HP were prepared to keep the blades in warranty for a three degree bump but no more.

latchkey 3y ago

My experience with running GPUs is that overclocking tends to go with undervolting and it has zero impact on longevity of the chips themselves. Other components like power supplies, with consumable or hand made things, like hand soldered components, are what end up failing. We had cards in the worst of the worst environments and they ran fine for years on end.

bayindirh 3y ago
I'd not be so sure, actually. Because we have seen other processors on the systems, like RAID or Ethernet cards go "insane" after some years. No overheat, no physical stress, nothing. Normal if a bit too much (HPC) work. Reboot the system, device just disappears, never to be never seen again. It generally starts after ~6 year mark. Sometimes device starts to corrupt things silently, but not always. However they too disappear after some time. Oh, sometimes GPUs do that, too.
- latchkey 3y ago
  The point being that you don't know which component on the board failed. If you look at the GPU chip itself, it might be just fine and it was just a capacitor that blew.
  - bayindirh 3y ago
    The GPUs we change arrive on a large board which hosts multiple GPUs with SXM interface. GPU itself arrives with its heat sink only, and we only change the GPU itself. Board is never replaced. Same for the RAID card. The processor has a couple of failure modes (no cache or no card), both directly related to RAID processor itself. Again same for the Ethernet cards we fry. They lose their MAC addresses, all pointing to in silica problems.
    - latchkey 3y ago
      Good point. I've also heard that there are fairly high rate of failures with high end nvidia stuff. I wonder why that is.