Undervolt i9-14900HX Laptop Newbie

[borkin793]

Just like the title said I'm new in the world of undervolting and can someone more experienced verify if what I did is correct and normal

My device: Lenovo Legion 7i (2024) gen 9 16IRX9 - RTX4070
No GPU undervolt because I want to focus on CPU side first
Balanced profile and balanced power plan because I want this undervolt profile to also work on battery

Here my result

Undervolt
Core= -160mV
P-cache = -159mV
E-cache = -30mV
system agent, iGPU, iGPU slice = -10mV

Cinebench score
Stock - Multi = 21267, Single = 2083
With Undervolt - Multi = 23564, Single = 1690
Idk why my single score went down, and what I noticed is after -100mV, my score stayed constant in both multi and single

Temps
Stock = 78-80 C
With undervolt = 75-77 C
Don't see much improvement

CPU package power under load/benchmark
Stock = 90W
With undervolt = 69W
Idk why this go down alot

What I did after undervolting
Ran both multi and single cinebench r23 30min each
Ran throttlestop bench with 7680m
Play mh wilds for 15+ min (averaging 75fps, dlss4 performance, high, 1440p settings), no noticeable fps change from stock
watch youtube on battery power with undervolt profile applied

So far, no crash only occasional fps dips, and slow down (Idk if its the game or undervolt)

So, based on those results,
1. Can anyone experienced verify if what I did was correct, and if this undervolt is good and normal
2. should I bump up my voltage to remove that stutter, fps dips, and slowdown to improve stability
3. how should I approach the other undervolt (E-cache, system agent, iGPU, and iGPU slice)
4. Any tips where I can go from here

Thank you

 

[unclewebb]

Not sure why you needed to post two different threads with the same information so I deleted the other thread you created. I will have a look at your settings.

Reducing the turbo ratios as much as you have has significantly reduced performance. You need much better cooling to get maximum performance out of a 14900HX.

Here is how a MSI Vector 17 does in Cinebench R23 with the exact same 14900HX.

Your undervolt settings are OK. I never bother undervolting the System Agent or the E Cache. Your laptop just seems to have a significant cooling problem. The Legion series usually have better cooling than that. You might have to repaste your laptop with Honeywell PTM 7950 to get the temperatures down and the performance up.

 

[borkin793]

Not sure why you needed to post two different threads with the same information so I deleted the other thread you created. I will have a look at your settings.

my bad I thought the other post got deleted. But thank you

 

[borkin793]

Not sure why you needed to post two different threads with the same information so I deleted the other thread you created. I will have a look at your settings.

Reducing the turbo ratios as much as you have has significantly reduced performance. You need much better cooling to get maximum performance out of a 14900HX.

Here is how a MSI Vector 17 does in Cinebench R23 with the exact same 14900HX.

Your undervolt settings are OK. I never bother undervolting the System Agent or the E Cache. Your laptop just seems to have a significant cooling problem. The Legion series usually have better cooling than that. You might have to repaste your laptop with Honeywell PTM 7950 to get the temperatures down and the performance up.

this laptop already have the ptm 7950 from factory. I tried putting the turbo ratio back to stock and it instantly bluescreened. Does it have to be in high performance mode ?

 

[unclewebb]

I tried putting the turbo ratio back to stock and it instantly bluescreened.

A stable undervolt should be stable at any speed. My 14900HX is not 100% stable at -160 mV. That is why I reduced the undervolt to -150 mV for the core and the P cache. I do not undervolt the System Agent and I do not undervolt the E cache.

Does it have to be in high performance mode ?

I have always had excellent success using the Windows High Performance power plan. I think not having the MHz constantly going up and down allows a person to reliably undervolt more. My light load temperatures are always good because I do not have a lot of tasks running in the background. Almost all laptop users prefer the Balanced power plan.

have the ptm 7950 from factory

I do not own a Lenovo Legion 7i so I have never tested how good the cooling is. All I know is that if the 14900HX Cinebench R23 scores are in the 21K to 23K range, you are losing a lot of performance due to poor cooling. If it was my laptop, I would probably pull it apart to make sure that the factory did a good job applying the PTM 7950. Maybe the heatsink is not as tight as it should be.

The problem might just be that you live in a very hot climate. Move to Canada where I live and your cooling problems will be solved.

 

[borkin793]

A stable undervolt should be stable at any speed. My 14900HX is not 100% stable at -160 mV. That is why I reduced the undervolt to -150 mV for the core and the P cache. I do not undervolt the System Agent and I do not undervolt the E cache.


I have always had excellent success using the Windows High Performance power plan. I think not having the MHz constantly going up and down allows a person to reliably undervolt more. My light load temperatures are always good because I do not have a lot of tasks running in the background. Almost all laptop users prefer the Balanced power plan.


I do not own a Lenovo Legion 7i so I have never tested how good the cooling is. All I know is that if the 14900HX Cinebench R23 scores are in the 21K to 23K range, you are losing a lot of performance due to poor cooling. If it was my laptop, I would probably pull it apart to make sure that the factory did a good job applying the PTM 7950. Maybe the heatsink is not as tight as it should be.

The problem might just be that you live in a very hot climate. Move to Canada where I live and your cooling problems will be solved.

I've tried it again today, same balanced power plan and same balanced profile on lenovo vantage
better result but temps are higher, and I'm getting more red power sign on throttle stop

I'm thinking that lenovo balanced mode really isn't suited for tweaking, and I'll have to try it again on high performance power plan tommorow

and yes I am living somewhere with hotter climate

A stable undervolt should be stable at any speed. My 14900HX is not 100% stable at -160 mV. That is why I reduced the undervolt to -150 mV for the core and the P cache. I do not undervolt the System Agent and I do not undervolt the E cache.


I have always had excellent success using the Windows High Performance power plan. I think not having the MHz constantly going up and down allows a person to reliably undervolt more. My light load temperatures are always good because I do not have a lot of tasks running in the background. Almost all laptop users prefer the Balanced power plan.


I do not own a Lenovo Legion 7i so I have never tested how good the cooling is. All I know is that if the 14900HX Cinebench R23 scores are in the 21K to 23K range, you are losing a lot of performance due to poor cooling. If it was my laptop, I would probably pull it apart to make sure that the factory did a good job applying the PTM 7950. Maybe the heatsink is not as tight as it should be.

The problem might just be that you live in a very hot climate. Move to Canada where I live and your cooling problems will be solved.

A stable undervolt should be stable at any speed. My 14900HX is not 100% stable at -160 mV. That is why I reduced the undervolt to -150 mV for the core and the P cache. I do not undervolt the System Agent and I do not undervolt the E cache.


I have always had excellent success using the Windows High Performance power plan. I think not having the MHz constantly going up and down allows a person to reliably undervolt more. My light load temperatures are always good because I do not have a lot of tasks running in the background. Almost all laptop users prefer the Balanced power plan.


I do not own a Lenovo Legion 7i so I have never tested how good the cooling is. All I know is that if the 14900HX Cinebench R23 scores are in the 21K to 23K range, you are losing a lot of performance due to poor cooling. If it was my laptop, I would probably pull it apart to make sure that the factory did a good job applying the PTM 7950. Maybe the heatsink is not as tight as it should be.

The problem might just be that you live in a very hot climate. Move to Canada where I live and your cooling problems will be solved.

I saw jarrodtech's review on the same device and he also saw similar results to mine. Whatever reason the cpu clock just won't go past 3600 ish mHz even in hugh performance mode and stress test. It seems like lenovo might actually put a lock/limit from factory

 

[unclewebb]

Whatever reason

The log file shows lots of PL1 power limit throttling right at 90W. Some manufacturers can program an embedded controller EC to force lower turbo power limits than what ThrottleStop lets you set. That is the reason for throttling showing up over and over again in the log file.

Even if you found a way to bypass this power limit, your CPU is overheating and thermal throttling at the 110W to 120W level. To put things in perspective, an undervolted 14900HX needs 230W so the P and E cores can both run at full speed. The poor cooling and power limit throttling has crippled your Lenovo Legion laptop. There is no real fix for bad design.

 

[borkin793]

The log file shows lots of PL1 power limit throttling right at 90W. Some manufacturers can program an embedded controller EC to force lower turbo power limits than what ThrottleStop lets you set. That is the reason for throttling showing up over and over again in the log file.

Even if you found a way to bypass this power limit, your CPU is overheating and thermal throttling at the 110W to 120W level. To put things in perspective, an undervolted 14900HX needs 230W so the P and E cores can both run at full speed. The poor cooling and power limit throttling has crippled your Lenovo Legion laptop. There is no real fix for bad design.

Yes. I noticed this too when watching multiple review videos on this device, esp from jarrodstech. He noticed that lenovo put a cpu performance cap that can't be removed even on performance and custom mode essentially giving us an underclocked version on the 14900hx

He also got max boost p core clock to be around 3600-3800 range

 

[AleXXX666]

Not sure why you needed to post two different threads with the same information so I deleted the other thread you created. I will have a look at your settings.

Reducing the turbo ratios as much as you have has significantly reduced performance. You need much better cooling to get maximum performance out of a 14900HX.

Here is how a MSI Vector 17 does in Cinebench R23 with the exact same 14900HX.

Your undervolt settings are OK. I never bother undervolting the System Agent or the E Cache. Your laptop just seems to have a significant cooling problem. The Legion series usually have better cooling than that. You might have to repaste your laptop with Honeywell PTM 7950 to get the temperatures down and the performance up.

Well sorry that's obvious. In laptop, you'd choose from cooling OR performance. No better choice lol
I'd reduce perf for constant temps no more than 80-85 maybe as CPU is already good anyway...