how much can you undervolt an i7 7500u in a stealth?

currently i am on core voltage offset of

-.0.105V

am i doing it right shall i try -0.110

?

 

Most Kaby/Sky CPUs do -100mV. Few that I've seen go higher, though. I'd probably settle at that, especially considering Razer's iffy power delivery.

 

If you are not getting any BSOD on load or idle then it is fine. The ULV chips, as in the stealth, tend to accept less undervolt than the bigger brother HQ chips. You can also try undervolting the iGPU, but take it easy...something like 60mV and go from there....maybe up to 80.

 

Ringbus aka Cache voltage is locked to IA/Core voltage in XTU. So if you use XTU you will not get any lower than what the Cache UV limit is.
But if you would use Throttlestop you can change those two settings independently.
My 7700HQ can undervolt around 110mv with both locked together. Unlocked I can undevolt the cores to around 140mv.
Also you should be aware that Cache/Ringbus is the main interconnect of the CPU internally and to your system which tends to cause instability all over the place when undervolted too much. I recommend not to undevolt Cache/Ringbus any more than 100mv.

 

So on your Kaby RB you have -100mV on the ring and -140mV on the core? That is impressive, I set mine the same, but I will try increasing the core offset and decreasing the ring offset.

 

Actually I use -63.5mv on the ring and -135mv on the core. -140mv works, but I like to keep a little room for ambient temperature variation.

Would be interesting to hear your results with a skylake cpu.

 

tbh i was on -0.100

and it was stable but sumehow the computer was slugish

 

don't undervolt iGPU and use default value 0.0

 

Any reason not to undervolt the iGPU?

 

You might get strange stutters while using iGPU on Windows UI. You are welcome to try it.

 

Interesting; I haven't noticed that. I did not know about the ring/core voltage, either. I will try decreasing my ring undervolt and increase the core undervolt.

 

Use same values for CPU, cache, Analog IO and System Agent, so if undervolt causes instability you can decrease everything for easier diagnostic/troubleshooting.

 

core/cache can do at least 50mv

analog/sa is +10mv compared to core/cache

igpu at least 45


Undervolted on an i5 7300U

 

I was able to get -80mV on all parts with i5 7300.

 

In my case (i7-7500U) I've managed to go -80 mV on the CPU, going under that threshold gives me an almost instant BSOD.
For GPU I've gone for -60 mV, as I read that GPU should not be undervolted that much (so it's possible I could go lower). Though the ThrottleStop guide says the values for CPU and GPU should be the same... And earlier in this thread someone said that GPU should not be undervolted at all.

 

Undervolting the GPU should be harmless - if you go too low you'll just crash and need to reset.

 

My i7 7500, stable at -90 mV, the difference is noticeable when playing with the core setting CPU intensive games like AC Origins, without it the game would crash due thermal that goes over 90 that bring unstable FPS (stuttering because throttling) in my guess, with that uV value I keep the thermal under 89 and finished the game. On other games like OW, destiny 2 I don’t need uVing.