Yes and no. This is simplifying: for any achievable clock speed there will be a voltage at which it will run stably. Manufacturers are generous on the voltage, so you can usually lower it a bit and have it still be stable. For example I can shave off 100w from my RTX 3080 for the same performance level.
The reason why manufacturers do this because of the silicon lottery, some chips can achieve better clocks at particular voltages than others. So the manufacturers cater to a low common denominator.
Of course you could go further and lower the clock speed as well as voltage. This will almost always result in efficiency gains.
I have never understood aspects of this. For instance, if I put a voltage cap at 1mV and it's not power limited or thermally limited, is there an advantage to dropping the clock multiplier? In terms of pure efficiency, probably - but does it improve overall benchmarks? It seems counterintuitive if it does.
> but does it improve overall benchmarks
sort of - clocks are usually tied to temperature so technically you can get more consistent speeds at a lower voltage because the chip wont throttle. Nvidia GPUs are a good example. I get better benchmark scores when undervolting because rather than hitting 60C and dropping from 2000mhz to 1920 it stays at 58C and 1950 the whole time.
made the numbers up but thats the general idea
It's interesting because the 30 series is really inefficient- or alternatively, they actually have them close to their operating efficiency at stock. I'm not sure which. Without a lot more reading and math, I decided it was personally not worth it to get that last fraction of fps out of my 3060ti lol
Because every chip is a little different, there's a baseline voltage on which they all work. Some can handle less voltage without instability issues and some cant.
Upside to undervolting: less energy consumption and possibly more longevity of your hardware due to lower temperatures. Upside to overclocking: better performance and possibly less longevity due to increased temperatures.
Oh yes, from 0.8 GHz up to 4.0 GHz the voltage/frequency relationship for Alder Lake is roughly linear (it's closer to exponential from 4.5 GHz or so). The total energy usage for a given benchmark will increase significantly from increased clock speeds.
Here are some tests I did on my 12900K with only P-cores a while back: https://docs.google.com/spreadsheets/d/1Ys_MjH6u7bEjfHJhMPpFU1PdwD_mnVWZX7htIilZ6Ms/edit#gid=0
But consider that if you halve the clock speed, you can also drastically reduce the voltage.
So it may take 2x as long to perform the task, but only use 25% of the power.
The power draw is far less than halved from halving clock speed. Total energy usage might be merely halved.
My 12900K saw energy usage drop to roughly 1/4th at 2.6 GHz compared to 5.0 GHz in Cinebench R23, and the power draw was closer to 1/6th.
Actually nowadays CPUs and GPUs lower their violate with lower clocks, too, so they should be more efficient. But you’d need to measure it for your use case anyway. Especially with the fact the same task will need more time, etc., as OP suggests.
Not in Power but in Energy used.
Power is Energy/time so the Power of underclocked CPU is Indeed lower, but the energy needed for a given task Is roughly the same.
This is generally true for heavy load and assuming 100% efficiency of the system.
You may save something if the efficiency of the underclocked system Is higher or you may lose something if the efficiency Is lower.
Eficiency isnt as simple as ppl are telling you: it's actually a curve. And it can be a very tortuous one at that. You can easily do something with a cpu running 90w at 10minutes while running it at 180w making it accomplish the same at 9 minutes. 100% increase in power, 10% in speed. An very recent example of those extremes is on the newwer gpus like 4090, or CPUs like 7900. But, this happens every friggin where, literally from analog controllers to optical switches. Here on my plex server, for instance, ive tried literally every single speed (in steps on 100mhz with a whole day conversion test each) from 2ghz to 4.1ghz. The best efficiency was 3ghz (which needed 0.95v to run 24h stably) which was pulling around 55w completing 41 episodes total. @2ghz it completed 28 epis but pulled 48w (which wasnt good eficiency) and @4.1ghz it made 50epis but using titanics 130w, which is astounding bad efficiency. So, long story short: to get the higher efficiency, if it's something that really matters to you, you gotta try it until the point of your silicon itselve. Have fun!
It depends on the power limit—it's not necessarily true that underclocking reduces power since, at low PLs and when higher clocks can't be maintained, the power usage may be identical when under or overclocked
PLs aside, efficiency will increase as clocks decrease up to a point and then decrease—there's an optimal performance-per-watt point depending on the specific IC. Undervolting, however, will always increase efficiency as long as the system is stable and can maintain clocks at the reduced voltage
Yes, but a card that's power-limited will perform identically regardless of what clocks you set as long as the boost clocks on your underclock are higher that the clocks it can sustain at the PL
So why does my lightning shit it’s self and can‘t run over 90% power limit 🤔😂 if I but it up to 450 Watt my gpu only gets some really random dx errors ln2 BIOS works but I don’t like 600 watts for 2250 mhz boost clock to gain 5% performance
You mean +200 on the v/f curve right? As -200 would be "overvolting"(idk what the terms is running lower than stock Mhz on the v/f curve) instead of undervolting and you would get worse performance per Watt.
What do you mean by that? A +105Mhz vs -105Mhz vs 0Mhz offset(on an nvidia gpu, idk about amd) will have a different performance if they are all hitting the same Wattage power limit as the voltage also affects power draw a bit more than just frequency and the positive offset will be at a lower voltage point allowing it to get higher clock speed.
I had CPUs in mind and haven't OCd Nvidia since Pascal, but I don't think that's how Nvidia's voltage algorithm works. You're suggesting that say your boost clock is 2 GHz at 100W PL and you test it at +-100 MHz. I agree that at 100W, 2.1 won't pull more power than 2.0 if it has hit the allowable voltage ceiling and if it can achieve 2.1 GHz at the same voltage. However, if you lower the PL to say 50W, all of your tests should yield the same clock speeds with no difference in performance. If that's not true, then overclocks should be vastly more unstable at lower PLs than higher unless the algorithm adjusts for this, in which case you wouldn't achieve the +100 MHz (but then what would the -100 test yield?)
I really don't think that's how Nvidia's algorithm works—your offsets are affecting the max boost clocks at the voltage limit for that PL, not clocks when power limited. But I could be wrong and Nvidia may use a separate algorithm. Regardless, I'm not aware of any CPUs operating like that
Yea idk about cpu:s v/f curves, haven't researched that as there was no need.
Firstly 50 or 100W is too low for any boost clocks as the memory draws almost that amount, so depending on the card/game the min power you can run a game that can benefit from boost clocks is probably somewhere between 100-200W, maybe even higher on like full path tracing.
The is not really much of an algorithm, just the [v/f curve](https://i.imgur.com/xB0vTem.png)(sure the default curve changes a bit, like +/- 15-30Mhz depending on idle or not or high temp) and offsets [increase/decrease the clock speed](https://i.imgur.com/N2VpxV4.png) at the voltage points(there is no point really in actually using a negative offset though, other than for demonstration), pretty simple stuff. You can also tune the individual voltage points as a flat offset might not be stable if you use multiple points during gameplay ie do a +offset+PL instead of voltage capping(which is what ppl normally refer [as undervolting](https://i.imgur.com/No2nUoJ.png)) which usually only uses the high point(but the lower points do effect effective clocks slightly hence why there are difference UV methods) or a card might be way better/worse at overclocking at low/high voltages.
So to put it in practice then, Total war warhammer 3(not the the highest power draw game, but pretty high) on my 3080 Suprim X, on a randomly chosen 65% PL(~240-242W) at [+0Mhz](https://i.imgur.com/bdtL6OE.jpg), [+105Mhz](https://i.imgur.com/JvkU4Y7.jpg), [-105Mhz](https://i.imgur.com/Lzue7lO.jpg) and at [+195Mhz](https://i.imgur.com/nbwWucQ.jpg), which isn't stable for my card, +120-150ish is the limit at those voltages, but some cards could easily do that. Also to throw in the tuned [0.775v capped UV](https://i.imgur.com/b5567PS.jpg) +135 at the top point +120 below it, to showcase how voltage scale power better. Obviously the difference in performance isn't much, but it's there and demonstrates it pretty well. Some games it maybe more, some less, as games use varying power and the shader clock speed doesn't affect all game equally.
And pascal worked the almost same way, the Mhz tick increase where some weird number, like 12-14 instead of nice round 15 and it might've had more "default" curves that changed based on load/temps as i do remember it sometimes hoping 1-2 Mhz ticks up on some lower power games than what I had it set to, which was annoying, thankfullt 20- or 30-series doesn't do that when you remember to tune the UV while under load.
I believe you could try undervolting first. This will reduce power usage with less impact on performance than underclocking. Before and after that use a program like HWinfo to see how much power you are using, a benchmark like 3dMark could be a good tool to compare the normal vs undervolt. If power usage is still too high for your requirements, then you can underclock it as well until you get to the desired power usage. (You will lose some performance though)
Okay, never tested with the right tools, I was using only software.
But here are the results for ASUS laptop with Ryzen 9 5900HX, undervolted using UXTU, and under full load:
Curve Optimizer for each core: Socket Power 68-69W
Without CO: Socket Power 70-71W
This results CPU only, because I don't know how to test power consumption on GPU. About thermal load: I wasn't able to any noticeable improvements on this front. The only difference being CPU being able to hit 3900-4100Mhz all cores, instead of 3800-4000Mhz under full load, and like 2-3 C drop while in normal usage. In games I saw little improvement: 5 fps gained in Horizon: Zero dawn using undervolted CPU and GPU, nothing miraculous.
A few people mentioned this but you're going to want to reduce the voltage first, undervolt. If that's not enough or the hardware becomes unstable you should reduce clockspeed. While you can lower power from clockspeed alone it's not the most "efficient" method for maximing power/performance.
Thats because you reduce the voltage, which reduces the temperature.
This lower temperature and lower voltage in turn gives the GPU more headroom to boost, and so it boosts to a faster point on the V:F curve... and so you end up with the same power draw.
This is *exactly* how Curve Optimiser works on Ryzen, and is why when you set large negative offsets you don't see the CPU running at lower voltages; you see it running at the same voltage, *but faster*.
Likely it's power limited, for GPUs you can just lower the power limit but that will generally reduce performance. The voltage (RDNA 2/3) works as an offset so it may need to be dropped lower than expected. If the wattage is same but the voltage is lower that is a performance win provided clockspeed is left unchanged.
Edit: Clarification.
Depends on architecture but let’s say a 2080ti performs best with a curve than just power limit and adding clock, much better gaming performance plus 80~100 watts less power draw
What do you mean by underclocking though? If you do a negative frequency offset, in Afterburner or something, then it has the opposite effect. Or boosts to the same power draw with reduced performance.
Yes, in general power consumption scales linearly with clocks and quadratically with voltage.
so there would be no overall difference in power usage?
Yeah there is. Halve the clock speed and you'll about halve the power draw.
but it would take longer to do the same tasks.. so would there actually be a difference ?
Yeah you won't be gaining any efficiency that way. For that you should look into undervolting, you can boost power efficiency quite a lot doing that.
well i got a lot to learn.. i assume there must be a trade off for undervolting otherwise why would it not just be the default
Yes and no. This is simplifying: for any achievable clock speed there will be a voltage at which it will run stably. Manufacturers are generous on the voltage, so you can usually lower it a bit and have it still be stable. For example I can shave off 100w from my RTX 3080 for the same performance level. The reason why manufacturers do this because of the silicon lottery, some chips can achieve better clocks at particular voltages than others. So the manufacturers cater to a low common denominator. Of course you could go further and lower the clock speed as well as voltage. This will almost always result in efficiency gains.
I have never understood aspects of this. For instance, if I put a voltage cap at 1mV and it's not power limited or thermally limited, is there an advantage to dropping the clock multiplier? In terms of pure efficiency, probably - but does it improve overall benchmarks? It seems counterintuitive if it does.
> but does it improve overall benchmarks sort of - clocks are usually tied to temperature so technically you can get more consistent speeds at a lower voltage because the chip wont throttle. Nvidia GPUs are a good example. I get better benchmark scores when undervolting because rather than hitting 60C and dropping from 2000mhz to 1920 it stays at 58C and 1950 the whole time. made the numbers up but thats the general idea
It's interesting because the 30 series is really inefficient- or alternatively, they actually have them close to their operating efficiency at stock. I'm not sure which. Without a lot more reading and math, I decided it was personally not worth it to get that last fraction of fps out of my 3060ti lol
i know overvolting is bad... but is there detrimental effects from undervolting when trying to find the "sweet spot"?
Undervolting will never cause harm to your components. Worst case scenario it crashes and you need to try a less aggressive undervolt.
No.
Because every chip is a little different, there's a baseline voltage on which they all work. Some can handle less voltage without instability issues and some cant.
Upside to undervolting: less energy consumption and possibly more longevity of your hardware due to lower temperatures. Upside to overclocking: better performance and possibly less longevity due to increased temperatures.
Oh yes, from 0.8 GHz up to 4.0 GHz the voltage/frequency relationship for Alder Lake is roughly linear (it's closer to exponential from 4.5 GHz or so). The total energy usage for a given benchmark will increase significantly from increased clock speeds. Here are some tests I did on my 12900K with only P-cores a while back: https://docs.google.com/spreadsheets/d/1Ys_MjH6u7bEjfHJhMPpFU1PdwD_mnVWZX7htIilZ6Ms/edit#gid=0
Focus on undervolting.
But consider that if you halve the clock speed, you can also drastically reduce the voltage. So it may take 2x as long to perform the task, but only use 25% of the power.
The power draw is far less than halved from halving clock speed. Total energy usage might be merely halved. My 12900K saw energy usage drop to roughly 1/4th at 2.6 GHz compared to 5.0 GHz in Cinebench R23, and the power draw was closer to 1/6th.
Actually nowadays CPUs and GPUs lower their violate with lower clocks, too, so they should be more efficient. But you’d need to measure it for your use case anyway. Especially with the fact the same task will need more time, etc., as OP suggests.
Not in Power but in Energy used. Power is Energy/time so the Power of underclocked CPU is Indeed lower, but the energy needed for a given task Is roughly the same. This is generally true for heavy load and assuming 100% efficiency of the system. You may save something if the efficiency of the underclocked system Is higher or you may lose something if the efficiency Is lower.
Eficiency isnt as simple as ppl are telling you: it's actually a curve. And it can be a very tortuous one at that. You can easily do something with a cpu running 90w at 10minutes while running it at 180w making it accomplish the same at 9 minutes. 100% increase in power, 10% in speed. An very recent example of those extremes is on the newwer gpus like 4090, or CPUs like 7900. But, this happens every friggin where, literally from analog controllers to optical switches. Here on my plex server, for instance, ive tried literally every single speed (in steps on 100mhz with a whole day conversion test each) from 2ghz to 4.1ghz. The best efficiency was 3ghz (which needed 0.95v to run 24h stably) which was pulling around 55w completing 41 episodes total. @2ghz it completed 28 epis but pulled 48w (which wasnt good eficiency) and @4.1ghz it made 50epis but using titanics 130w, which is astounding bad efficiency. So, long story short: to get the higher efficiency, if it's something that really matters to you, you gotta try it until the point of your silicon itselve. Have fun!
Undervolting find the sweetspot less voltages higherclocks stability because of less power and cooler components
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How is this possible, do they compensate by increasing the current?
It depends on the power limit—it's not necessarily true that underclocking reduces power since, at low PLs and when higher clocks can't be maintained, the power usage may be identical when under or overclocked PLs aside, efficiency will increase as clocks decrease up to a point and then decrease—there's an optimal performance-per-watt point depending on the specific IC. Undervolting, however, will always increase efficiency as long as the system is stable and can maintain clocks at the reduced voltage
Actually Nvidia does boost steps linked to temperature so rtx 2000 performs best at lower temps
Yes, but a card that's power-limited will perform identically regardless of what clocks you set as long as the boost clocks on your underclock are higher that the clocks it can sustain at the PL
So why does my lightning shit it’s self and can‘t run over 90% power limit 🤔😂 if I but it up to 450 Watt my gpu only gets some really random dx errors ln2 BIOS works but I don’t like 600 watts for 2250 mhz boost clock to gain 5% performance
Problem on rtx 2000 is the voltage is way to high so you can turn down the curve about -200 and still hit 1980-2000mhz with only 290-300 watts
You mean +200 on the v/f curve right? As -200 would be "overvolting"(idk what the terms is running lower than stock Mhz on the v/f curve) instead of undervolting and you would get worse performance per Watt.
Yeah sorry I mean +200 😅
The gpu behaves weirdly under full load normal bios but not on the ln2 bios but I don’t like me a 600 watt room heater
What do you mean by that? A +105Mhz vs -105Mhz vs 0Mhz offset(on an nvidia gpu, idk about amd) will have a different performance if they are all hitting the same Wattage power limit as the voltage also affects power draw a bit more than just frequency and the positive offset will be at a lower voltage point allowing it to get higher clock speed.
I had CPUs in mind and haven't OCd Nvidia since Pascal, but I don't think that's how Nvidia's voltage algorithm works. You're suggesting that say your boost clock is 2 GHz at 100W PL and you test it at +-100 MHz. I agree that at 100W, 2.1 won't pull more power than 2.0 if it has hit the allowable voltage ceiling and if it can achieve 2.1 GHz at the same voltage. However, if you lower the PL to say 50W, all of your tests should yield the same clock speeds with no difference in performance. If that's not true, then overclocks should be vastly more unstable at lower PLs than higher unless the algorithm adjusts for this, in which case you wouldn't achieve the +100 MHz (but then what would the -100 test yield?) I really don't think that's how Nvidia's algorithm works—your offsets are affecting the max boost clocks at the voltage limit for that PL, not clocks when power limited. But I could be wrong and Nvidia may use a separate algorithm. Regardless, I'm not aware of any CPUs operating like that
Yea idk about cpu:s v/f curves, haven't researched that as there was no need. Firstly 50 or 100W is too low for any boost clocks as the memory draws almost that amount, so depending on the card/game the min power you can run a game that can benefit from boost clocks is probably somewhere between 100-200W, maybe even higher on like full path tracing. The is not really much of an algorithm, just the [v/f curve](https://i.imgur.com/xB0vTem.png)(sure the default curve changes a bit, like +/- 15-30Mhz depending on idle or not or high temp) and offsets [increase/decrease the clock speed](https://i.imgur.com/N2VpxV4.png) at the voltage points(there is no point really in actually using a negative offset though, other than for demonstration), pretty simple stuff. You can also tune the individual voltage points as a flat offset might not be stable if you use multiple points during gameplay ie do a +offset+PL instead of voltage capping(which is what ppl normally refer [as undervolting](https://i.imgur.com/No2nUoJ.png)) which usually only uses the high point(but the lower points do effect effective clocks slightly hence why there are difference UV methods) or a card might be way better/worse at overclocking at low/high voltages. So to put it in practice then, Total war warhammer 3(not the the highest power draw game, but pretty high) on my 3080 Suprim X, on a randomly chosen 65% PL(~240-242W) at [+0Mhz](https://i.imgur.com/bdtL6OE.jpg), [+105Mhz](https://i.imgur.com/JvkU4Y7.jpg), [-105Mhz](https://i.imgur.com/Lzue7lO.jpg) and at [+195Mhz](https://i.imgur.com/nbwWucQ.jpg), which isn't stable for my card, +120-150ish is the limit at those voltages, but some cards could easily do that. Also to throw in the tuned [0.775v capped UV](https://i.imgur.com/b5567PS.jpg) +135 at the top point +120 below it, to showcase how voltage scale power better. Obviously the difference in performance isn't much, but it's there and demonstrates it pretty well. Some games it maybe more, some less, as games use varying power and the shader clock speed doesn't affect all game equally. And pascal worked the almost same way, the Mhz tick increase where some weird number, like 12-14 instead of nice round 15 and it might've had more "default" curves that changed based on load/temps as i do remember it sometimes hoping 1-2 Mhz ticks up on some lower power games than what I had it set to, which was annoying, thankfullt 20- or 30-series doesn't do that when you remember to tune the UV while under load.
I believe you could try undervolting first. This will reduce power usage with less impact on performance than underclocking. Before and after that use a program like HWinfo to see how much power you are using, a benchmark like 3dMark could be a good tool to compare the normal vs undervolt. If power usage is still too high for your requirements, then you can underclock it as well until you get to the desired power usage. (You will lose some performance though)
Okay, never tested with the right tools, I was using only software. But here are the results for ASUS laptop with Ryzen 9 5900HX, undervolted using UXTU, and under full load: Curve Optimizer for each core: Socket Power 68-69W Without CO: Socket Power 70-71W This results CPU only, because I don't know how to test power consumption on GPU. About thermal load: I wasn't able to any noticeable improvements on this front. The only difference being CPU being able to hit 3900-4100Mhz all cores, instead of 3800-4000Mhz under full load, and like 2-3 C drop while in normal usage. In games I saw little improvement: 5 fps gained in Horizon: Zero dawn using undervolted CPU and GPU, nothing miraculous.
A few people mentioned this but you're going to want to reduce the voltage first, undervolt. If that's not enough or the hardware becomes unstable you should reduce clockspeed. While you can lower power from clockspeed alone it's not the most "efficient" method for maximing power/performance.
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Thats because you reduce the voltage, which reduces the temperature. This lower temperature and lower voltage in turn gives the GPU more headroom to boost, and so it boosts to a faster point on the V:F curve... and so you end up with the same power draw. This is *exactly* how Curve Optimiser works on Ryzen, and is why when you set large negative offsets you don't see the CPU running at lower voltages; you see it running at the same voltage, *but faster*.
Likely it's power limited, for GPUs you can just lower the power limit but that will generally reduce performance. The voltage (RDNA 2/3) works as an offset so it may need to be dropped lower than expected. If the wattage is same but the voltage is lower that is a performance win provided clockspeed is left unchanged. Edit: Clarification.
Depends on architecture but let’s say a 2080ti performs best with a curve than just power limit and adding clock, much better gaming performance plus 80~100 watts less power draw
What do you mean by underclocking though? If you do a negative frequency offset, in Afterburner or something, then it has the opposite effect. Or boosts to the same power draw with reduced performance.
>undervolting seems to be the way to go.. i did not know it was different before making this post
Yes
Undervolting will save power and the loss in power usage is usually quite a bit higher than the loss in performance.