# What Voltages to Use for Underclocking RAM to 2933 and 2666?



## avrona (Jul 17, 2019)

I have two sticks of Vengeance LPX 3000mhz RAM, what voltages should I set them for when underclocking them to 2933MHz and 2666MHz?


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## TheLostSwede (Jul 17, 2019)

1.2V is standard Voltage for DDR4, but maybe not at 2933. Try 1.3 or 1.25V.
Why would you want to underclock the RAM though?


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## avrona (Jul 17, 2019)

TheLostSwede said:


> 1.2V is standard Voltage for DDR4, but maybe not at 2933. Try 1.3 or 1.25V.
> Why would you want to underclock the RAM though?


So do I do 1.3V then for both 2666 and 2933?


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## TheLostSwede (Jul 17, 2019)

avrona said:


> So do I do 1.3V then for both 2666 and 2933?


2666 ought to run at 1.2V, but you're simply going to have to try. I mean, the system either works, or it doesn't.
You might have to loosen up the timings if you want low Voltage and higher speeds as well.


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## kapone32 (Jul 17, 2019)

You would have to see if your RAM supports 1.2 but I would not worry about that as undervolting RAM is actually pointless. When you pick the speed in the BIOS it should adjust the voltage accordingly but will stay at 1.35 which is the default setting for the RAM you have. I guess you have not updated your specs in a while as it still shows you have an FX processor.


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## avrona (Jul 17, 2019)

kapone32 said:


> You would have to see if your RAM supports 1.2 but I would not worry about that as undervolting RAM is actually pointless. When you pick the speed in the BIOS it should adjust the voltage accordingly but will stay at 1.35 which is the default setting for the RAM you have. I guess you have not updated your specs in a while as it still shows you have an FX processor.


My BIOS doesn't adjust them automatically so that's why I'm asking here. Also no I'm not running on an fx on my main PC now.


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## TheMadDutchDude (Jul 17, 2019)

You still haven’t answered why you want to under volt and clock your RAM...


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## GoldenX (Jul 18, 2019)

RAM undervolting wont help much in reducing power consumption.
Anyway, I'm currently at 2933MHz at the standard 1.2v. With normal latencies, you should be able to archive something similar.


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## flmatter (Jul 18, 2019)

avrona said:


> Also no I'm not running on an fx on my main PC now.


You need to update your system specs so people can help you better. Yes the new motherboards have an auto setting for ram as well as XMP setting for OC profiles for ram. update your specs
Your ram 2933 will only run at the 2666 speeds as well. The default voltage for 2666 is fine as well. It is not recommended that you mix match ram and speeds because it can cause system instability and you will be back asking more questions why my system is sluggish or whatever.
Before you say again you do not have an auto setting  update your specs and or link your new motherboard.


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## Tatty_One (Jul 18, 2019)

I have Vengeance LPX Ram, I have gone the opposite way, stock voltage at 3000mhz is 1.30 for mine @ CL15 (I think), I can do 3200mhz at CL16 or 3100mhz @ CL15 both on 1.35V @ 1T.......... for you I would just be safe and set at 1.30v for either speeds and leave it there, I have no doubts 2666 would run at 1.25V but it's unlikely 2933 will unless you tweak timings accordingly.

If you really want to keep voltage low then maybe leave at 1.25v and you may be able to set 2666 @ CL14 and also at 1.25v you may get away with 2933 @ CL16, have a play.


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## avrona (Jul 18, 2019)

flmatter said:


> You need to update your system specs so people can help you better. Yes the new motherboards have an auto setting for ram as well as XMP setting for OC profiles for ram. update your specs
> Your ram 2933 will only run at the 2666 speeds as well. The default voltage for 2666 is fine as well. It is not recommended that you mix match ram and speeds because it can cause system instability and you will be back asking more questions why my system is sluggish or whatever.
> Before you say again you do not have an auto setting  update your specs and or link your new motherboard.


I think you just misunderstood my post. My RAM isn't 2933, it's 3000 stock, and I want to know what voltages to set it to when underclocking to 2933 and 2666.



GoldenX said:


> RAM undervolting wont help much in reducing power consumption.
> Anyway, I'm currently at 2933MHz at the standard 1.2v. With normal latencies, you should be able to archive something similar.


I'm not trying to reduce power consumption or anything so I just need to know what voltages to set them to so it's stable or whatever else, never really underclocked RAM before.


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## kapone32 (Jul 18, 2019)

avrona said:


> My BIOS doesn't adjust them automatically so that's why I'm asking here. Also no I'm not running on an fx on my main PC now.



Are you saying you don't have XMP profiles on your BIOS?


avrona said:


> I think you just misunderstood my post. My RAM isn't 2933, it's 3000 stock, and I want to know what voltages to set it to when underclocking to 2933 and 2666.
> 
> 
> I'm not trying to reduce power consumption or anything so I just need to know what voltages to set them to so it's stable or whatever else, never really underclocked RAM before.



All you have to do is enable the XMP profile and pick 2933 as the RAM speed. I doubt you will see a difference of any kind in terms of power draw. You will not see 1.2 volts at 2933 as that is only 67 away from the stock clock. BTW if you are on Ryzen it actually hurts performance to run at lower speeds. My thoughts are to leave the RAM as is and suck up the 2 cents a month premium for running at stock voltages.


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## avrona (Jul 18, 2019)

kapone32 said:


> Are you saying you don't have XMP profiles on your BIOS?
> 
> 
> All you have to do is enable the XMP profile and pick 2933 as the RAM speed. I doubt you will see a difference of any kind in terms of power draw. You will not see 1.2 volts at 2933 as that is only 67 away from the stock clock. BTW if you are on Ryzen it actually hurts performance to run at lower speeds. My thoughts are to leave the RAM as is and suck up the 2 cents a month premium for running at stock voltages.


I do have XMP, I just thought that only worked with overclocking, not underclocking, so I'll try just to use that then to underclock.


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## TheMadDutchDude (Jul 18, 2019)

XMP will run your modules at what they are rated at. You’re over complicating this for no reason, fella.


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## avrona (Jul 18, 2019)

TheMadDutchDude said:


> XMP will run your modules at what they are rated at. You’re over complicating this for no reason, fella.


I've never underclocked RAM before so I don't fully understand what needs to be done for it.


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## kapone32 (Jul 18, 2019)

avrona said:


> I've never underclocked RAM before so I don't fully understand what needs to be done for it.


 Just enable the XMP profile.


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## avrona (Jul 18, 2019)

So I turned on XMP and then lowered the multiplier to 2666. Is that it?


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## kapone32 (Jul 18, 2019)

avrona said:


> View attachment 127097
> So I turned on XMP and then lowered the multiplier to 2666. Is that it?



Exactly as long as it boots you will be good.


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## TheMadDutchDude (Jul 19, 2019)

Why not run it at 3000? I'm still so very confused...


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## Lightofhonor (Jul 19, 2019)

TheMadDutchDude said:


> Why not run it at 3000? I'm still so very confused...


Ryzen doesn't like 3000, so it normally goes to 2933.

I think the issue is/was he thought he needed to undervolt since it's downclocking. You don't need to undervolt, just leave it at 1.35v.

Maybe even try 1.4v and 3200


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## TheMadDutchDude (Jul 19, 2019)

Yep, run it at 3200 with a slight bump in voltage if that's the case.

I haven't heard of 3000 being an issue, but I haven't bothered checking either.


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## EarthDog (Jul 19, 2019)

Yeah... feels like half of a story. Did you try xmp and was it not stable? What's the whole story here?

What's the reason you want to use 2933? That is below the BASE spec of your CPU (which is 3200). AMD recommends 3600 speed, in fact. 

As far as what voltage... who knows exactly. You can try lowering it to the suggested 1.3 and see if that works....but there isnt a cookie cutter setting. You'll have to make some effort to check and test for stability.


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## biffzinker (Jul 19, 2019)

I've found out I can get away with 3200 MHz and 18-19-19-19-38  at 1.2v. Doesn't hurt to experiment with the settings.


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## TheMadDutchDude (Jul 19, 2019)

Crank that voltage! C18 is mega loose at 3200.


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## biffzinker (Jul 19, 2019)

TheMadDutchDude said:


> Crank that voltage! C18 is mega loose at 3200.


I was messing around with how loose the timings have to be to run 3200 MHz with the voltage restricted to 1.2v. Timings are tighter than a new set of Crucial DDR4-3200 though.

The timings can be tightened to C15-17-17


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## avrona (Jul 19, 2019)

biffzinker said:


> I was messing around with how loose the timings have to be to run 3200 MHz with the voltage restricted to 1.2v. Timings are tighter than a new set of Crucial DDR4-3200 though.
> 
> The timings can be tightened to C15-17-17


If having a high voltage for the RAM doesn't hurt it, then that's fine, I was just under the impression that you have to lower it for it to be stable at lower clocks the same way you up the voltage when overclocking.


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## TheMadDutchDude (Jul 19, 2019)

Not really. So I would just run yours at 3200. 

I run my RAM at 1.5v all day long, and running Bdie can take 1.7 or 1.8 daily without issue. So don’t be afraid. 

Leave it at 1.35 or 1.4v and set to 3200. Done.


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## avrona (Jul 19, 2019)

TheMadDutchDude said:


> Not really. So I would just run yours at 3200.
> 
> I run my RAM at 1.5v all day long, and running Bdie can take 1.7 or 1.8 daily without issue. So don’t be afraid.
> 
> Leave it at 1.35 or 1.4v and set to 3200. Done.


Thing is I'm trying to underclock it here, so I just thought I also needed to undervolt it as well when doing that for stability reasons or whatever else.


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## EarthDog (Jul 19, 2019)

avrona said:


> Thing is I'm trying to underclock it here, so I just thought I also needed to undervolt it as well when doing that for stability reasons or whatever else.



The thing is, you don't "need" to do anything when you undervolt. You CAN lower voltage a bit if its still stable. But clearly it wouldn't hurt it because 1.35V is its nominal voltage in the first place.

That said a change from 3K to 2.933K you likely can't lower it in the first place. If I was you, I wouldn't try and just leave it alone at whatever speed the sticks are rated for. 


You still have not answered why you would like to underclock the RAM. Even if it is for giggles, that is ok, but I think we all want to hear why you are doing this and running it below the base specification for the platform... it makes no sense from the outside without an explanation. What is your goal in underclocking? What do you think you are gaining by doing this?


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## avrona (Jul 19, 2019)

EarthDog said:


> The thing is, you don't "need" to do anything when you undervolt. You CAN lower voltage a bit if its still stable. But clearly it wouldn't hurt it because 1.35V is its nominal voltage in the first place.
> 
> That said a change from 3K to 2.933K you likely can't lower it in the first place. If I was you, I wouldn't try and just leave it alone at whatever speed the sticks are rated for.
> 
> ...


It's just an experiment for a video to show if there is a big difference in performance for Ryzen 3000 with different RAM speeds.


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## TheMadDutchDude (Jul 19, 2019)

Hate to burst your bubble, but there are hundreds of those already. It’s a very well known fact that memory performance directly corresponds to CPU performance.

Things get a little more interesting above 3733 on Zen2, as more speed nets you a worse performing result, but it will pick up again further on. I never bothered going past 4266 on my memory as the performance loss was horrid when considering that 3600 or 3733 was faster.


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## avrona (Jul 19, 2019)

Well I think I may have underclocked wrong or something as I get absolutely no difference in performance...


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## EarthDog (Jul 19, 2019)

avrona said:


> It's just an experiment for a video to show if there is a big difference in performance for Ryzen 3000 with different RAM speeds.


ahh.. it's been covered before online....FYI...at TPU even.








						AMD Zen 2 Memory Performance Scaling with Ryzen 9 3900X
					

We take a close look at memory scaling on AMD's new Zen 2 Ryzen 3900X, testing both application and gaming performance at seven different memory speed and timing combinations ranging from 2400 MHz all the way up to 4000 MHz.




					www.techpowerup.com
				




As weve said 3k to 2933 isnt going to show squat. 2933 to 3200 not much. There isnt a huge difference, especially on Intel. Ryzen yields more, but it was never a lot and such meager differences surely wont show much...not that you did it wrong.

 We're here to help, but... this has been covered already by pros who know what they are doing and use proper, empirical testing. Nothing wrong with having some fun though and playing!


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## Lightofhonor (Jul 19, 2019)

avrona said:


> Well I think I may have underclocked wrong or something as I get absolutely no difference in performance...


The difference between 3000 and 2933 is going to be margin or error.


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## avrona (Jul 19, 2019)

Lightofhonor said:


> The difference between 3000 and 2933 is going to be margin or error.


But the difference between 3000 and 2666 was also within what just seemed like the margin of error.


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## EarthDog (Jul 19, 2019)

avrona said:


> But the difference between 3000 and 2666 was also within what just seemed like the margin of error.


Did you read the article I linked? Its margin of error difference there too. A hair over 1%. From 2400 to 3600 was 3%.... as weve said multiple times already, you arent going to see much of a difference at all. 

What are you benchmarking with to determine this information?


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## avrona (Jul 19, 2019)

EarthDog said:


> Did you read the article I linked? Its margin of error difference there too. A hair over 1%. From 2400 to 3600 was 3%.... as weve said multiple times already, you arent going to see much of a difference at all.
> 
> What are you benchmarking with to determine this information?


Cinebench, Rainbow Six: Siege, Shadow of the Tomb Raider, Blender, and Time Spy.


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## EarthDog (Jul 19, 2019)

avrona said:


> Cinebench, Rainbow Six: Siege, Shadow of the Tomb Raider, Blender, and Time Spy.


Cool.

Now read that article and see what weve all been saying isnt BS.


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## Lightofhonor (Jul 19, 2019)

avrona said:


> Cinebench, Rainbow Six: Siege, Shadow of the Tomb Raider, Blender, and Time Spy.


Yeah, going by TPU's own article, you should see at most a 3% difference. 









						AMD Zen 2 Memory Performance Scaling with Ryzen 9 3900X
					

We take a close look at memory scaling on AMD's new Zen 2 Ryzen 3900X, testing both application and gaming performance at seven different memory speed and timing combinations ranging from 2400 MHz all the way up to 4000 MHz.




					www.techpowerup.com
				




Not something you are going to notice in real life. If you want to see the difference try 2133 vs 3600.


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