Undervolt help

[A1_Digest]

Hey guys i have an i7 13700k and wanted to undervolt it. my understanding is the speed will stay the same but the point of this is just to decrease heat? I have asus z790 p motherboard and want to know what settings to change to perform this.  Also in my mobo i have xmp set to xmp 2. thank you!

[RONOTHAN##]

2 minutes ago, A1_Digest said:

my understanding is the speed will stay the same but the point of this is just to decrease heat?

Yup, lower the power consumption/heat output but keep the same performance. 

 

There's a couple different ways of going about this, you can do an offset method or a static voltage method, and you can do this through software or the BIOS. Most of the steps are the same between all methods, but I'll try to highlight the differences and pros and cons of each. 

 

1. Get a baseline of performance/temps and decide on a stress test you'll be using. One of the ways instability can show up is by worsening performance, so having a baseline score is necessary to make sure you're not running into that. Cinebench works well enough for this task, though something a bit more intensive like Y-Cruncher could be a bit better depending. Next thing is to decide on a stress test. Personally, when I'm undervolting, I want to give the worst case scenario, and that would be Prime95 Small FFTs, but that might run into issues where it starts thermal throttling at stock settings and therefore irrelevant to the actual stability and you might need to go for something else. 
2. Set up how you'll be undervolting. 
   1. If you're going to be doing the static voltage method in the BIOS, find the VCore setting, set it to static mode, and set the VCore to 1.35V. Find the CPU multiplier and set it to 53 for the P cores and 42 for the E cores. Finally, find the LLC setting and set this to Mode 4. 
   2. If you're going to do the offset method in the BIOS, find the VCore setting, set it to offset mode, set it to negative, and enter 0.01V for a -0.01V undervolt. Nothing else to change
   3. If you're going to do this in software, download Intel XTU and install. You should find an option to chang ethe system's voltage, and set the mode to either offset or static depending on your preference and set it to either -0.01V or 1.35V respectively. If you're doing the static voltage mode, set the LLC setting in the BIOS to Mode 4.
3. Go back and run the benchmark, then the stress test for 5 minutes. Record the score to make sure it's not decreasing, and make sure it's not very unstable. 
   1. If it's stable, go back into the BIOS or XTU and lower the voltage by 0.01V and repeat. 
   2. If it's unstable, raise it 0.01V and continue. 
4. Do a stress test run for at least 2 hours to make sure the system is fully stable. If it crashes, raise the voltage 0.01V and repeat. 

As for the differences between the modes, I'll first talk about software vs. BIOS. Software undervolting takes much less time since you aren't constantly rebooting the system, while BIOS undervolting doesn't need to have XTU running at all times to function, as well as not requiring XTU to work in general (it's 50/50 whether it will work on a system in my experience, though admittedly I seem to be more in the minority with how unreliable it is). What you can do though is have the best of both worlds, do the majority of your undervolting in software through XTU, then before you go to do the long stress test transfer all the settings to the BIOS and uninstall XTU. 

 

As for static vs. offset, static will have higher idle power draw at the expense of being a bit more reliable in theory. With offset undervolting, you can sometimes run into issues where it will crash in lighter applications but not in heavy ones, and if you're going to run into clock stretching (performance going down for no reason while undervolting) it will be doing so with this method. Static voltages disable the types of functionality that can cause that to happen, and while it will cause idle temps and power draw to go up, your full and medium loads will still get the benefits of the undervolt. Most people are fine with the offset method, though figured I'd might as well mention the potential downsides to it.

 

As for how far you'll be able to undervolt, I've undervolted three different 13th gen chips (2 13600Ks and a 13700K), the worst of the three did -0.05V for an undervolt while the best of the three (this ended up being a golden sample) did a -0.15V undervolt, so you should land somewhere in that range, probably close to the -0.05V end. 

[A1_Digest]

4 hours ago, RONOTHAN## said:

Yup, lower the power consumption/heat output but keep the same performance. 

 

There's a couple different ways of going about this, you can do an offset method or a static voltage method, and you can do this through software or the BIOS. Most of the steps are the same between all methods, but I'll try to highlight the differences and pros and cons of each. 

 

1. Get a baseline of performance/temps and decide on a stress test you'll be using. One of the ways instability can show up is by worsening performance, so having a baseline score is necessary to make sure you're not running into that. Cinebench works well enough for this task, though something a bit more intensive like Y-Cruncher could be a bit better depending. Next thing is to decide on a stress test. Personally, when I'm undervolting, I want to give the worst case scenario, and that would be Prime95 Small FFTs, but that might run into issues where it starts thermal throttling at stock settings and therefore irrelevant to the actual stability and you might need to go for something else. 
2. Set up how you'll be undervolting. 
   1. If you're going to be doing the static voltage method in the BIOS, find the VCore setting, set it to static mode, and set the VCore to 1.35V. Find the CPU multiplier and set it to 53 for the P cores and 42 for the E cores. Finally, find the LLC setting and set this to Mode 4. 
   2. If you're going to do the offset method in the BIOS, find the VCore setting, set it to offset mode, set it to negative, and enter 0.01V for a -0.01V undervolt. Nothing else to change
   3. If you're going to do this in software, download Intel XTU and install. You should find an option to chang ethe system's voltage, and set the mode to either offset or static depending on your preference and set it to either -0.01V or 1.35V respectively. If you're doing the static voltage mode, set the LLC setting in the BIOS to Mode 4.
3. Go back and run the benchmark, then the stress test for 5 minutes. Record the score to make sure it's not decreasing, and make sure it's not very unstable. 
   1. If it's stable, go back into the BIOS or XTU and lower the voltage by 0.01V and repeat. 
   2. If it's unstable, raise it 0.01V and continue. 
4. Do a stress test run for at least 2 hours to make sure the system is fully stable. If it crashes, raise the voltage 0.01V and repeat. 

As for the differences between the modes, I'll first talk about software vs. BIOS. Software undervolting takes much less time since you aren't constantly rebooting the system, while BIOS undervolting doesn't need to have XTU running at all times to function, as well as not requiring XTU to work in general (it's 50/50 whether it will work on a system in my experience, though admittedly I seem to be more in the minority with how unreliable it is). What you can do though is have the best of both worlds, do the majority of your undervolting in software through XTU, then before you go to do the long stress test transfer all the settings to the BIOS and uninstall XTU. 

 

As for static vs. offset, static will have higher idle power draw at the expense of being a bit more reliable in theory. With offset undervolting, you can sometimes run into issues where it will crash in lighter applications but not in heavy ones, and if you're going to run into clock stretching (performance going down for no reason while undervolting) it will be doing so with this method. Static voltages disable the types of functionality that can cause that to happen, and while it will cause idle temps and power draw to go up, your full and medium loads will still get the benefits of the undervolt. Most people are fine with the offset method, though figured I'd might as well mention the potential downsides to it.

 

As for how far you'll be able to undervolt, I've undervolted three different 13th gen chips (2 13600Ks and a 13700K), the worst of the three did -0.05V for an undervolt while the best of the three (this ended up being a golden sample) did a -0.15V undervolt, so you should land somewhere in that range, probably close to the -0.05V end. 

is cpu system agent voltage the same as vcore thats all i see? i also cant find llc mode and or the cpu cores  im new to this sorry for the short reply im trying to figure this out. 

 

i tried going through bios i need step by step instructions as i cant find any of this

[RONOTHAN##]

16 minutes ago, A1_Digest said:

is cpu system agent voltage the same as vcore thats all i see? i also cant find llc mode and or the cpu cores  im new to this sorry for the short reply im trying to figure this out. 

 

i tried going through bios i need step by step instructions as i cant find any of this

No, system Agent isn't the same thing. It'll be called CPU Core voltage or something along those lines. 

 

I ended up selling my ASUS Z690 board, so I can't remember the exact names they call everything or where they put it. LLC settings will be in one of the submenus. 

 

If you want to put screen shots on here, I can tell you what submenus and everything they are, it's just that I haven't used an ASUS board in a bit and will need to jog my memory to say the exact settings (I'll see if I can find some BIOS screenshots of a similar board though to get the exact names though) 

[A1_Digest]

15 minutes ago, RONOTHAN## said:

No, system Agent isn't the same thing. It'll be called CPU Core voltage or something along those lines. 

 

I ended up selling my ASUS Z690 board, so I can't remember the exact names they call everything or where they put it. LLC settings will be in one of the submenus. 

 

If you want to put screen shots on here, I can tell you what submenus and everything they are, it's just that I haven't used an ASUS board in a bit and will need to jog my memory to say the exact settings (I'll see if I can find some BIOS screenshots of a similar board though to get the exact names though) 

here are some pics!

[RONOTHAN##]

32 minutes ago, A1_Digest said:

here are some pics!

It's the actual VRM Core value for the VCore setting, and the LLC setting is on DIGI+ VRM setting. 

[A1_Digest]

7 hours ago, RONOTHAN## said:

It's the actual VRM Core value for the VCore setting, and the LLC setting is on DIGI+ VRM setting. 

Thanks! So i i changed vcore and llc now last thing is where do i put in the values for the cpu cores?

[RONOTHAN##]

28 minutes ago, A1_Digest said:

Thanks! So i i changed vcore and llc now last thing is where do i put in the values for the cpu cores?

The settings labeled "performance core ratio" and "efficiency core ratio" respectively. You might need to set them to sync all cores first before you set the ratios. 

[A1_Digest]

1 hour ago, RONOTHAN## said:

The settings labeled "performance core ratio" and "efficiency core ratio" respectively. You might need to set them to sync all cores first before you set the ratios. 

i did it! 

 

so what voltages do i lower if my system is stable at current voltages? 

[RONOTHAN##]

3 hours ago, A1_Digest said:

i did it! 

 

so what voltages do i lower if my system is stable at current voltages? 

The VCore setting (VRM Core value). Do that until it's unstable.