Undervolting

[a_c_s]

Can anyone who has fooled with undervolting settings on the Epic 4G provide stable settings that you've toyed with?

I'm on Bonsai 4.0.1 and am trying out the Genocide kernel with custom undervolt settings.
Just trying to figure out what's reasonable without pushing too far and getting data corruption. I plan not to overclock, so frequencies I need to tweak are 1000, 800, 600, 400 and 200. I'm at -25 now, but can go a lot lower.

Can anyone provide any info or help? Did a search but did not find much on the topic that went into any real detail...

Thanks

 

[Skunkape60]

What's three point of undervolting?

Sent from my SPH-D700 using Tapatalk

 

[scoob]

a_c_s - I think that UV is kind of like overclocking in that each CPU is a little different in how much stress it can tolerate. That is probably why you can't find any tweaks set in stone- you gotta experiment.
I suggest going at -25 and play with it for a day and then go higher. I've read that around 1000mghz or higher, you dont want to UV at all or with great caution as that will freeze you phone faster.
Also- (I got this tip from another user) search for CPU Spy which will tell you at what speed your phone spends the most time in so you can concentrate at those speeds to mess with. Mine for example today spent most of its time at around 400...

keith- the way I understand it, UV lets to get more battery life out of your phone. Combine that with overclocking and you got a rocking phone that sucks less power. You might also try unclocking for the same effect but that isnt as fun...

 

[lattiboy]

I've read a lot about UV-ing and the consensus seems to be bias of heavily undervolting lower frequencies and leaving the higher frequencies closer to stock. I have mine set:

1200Mhz - 50
1000Mhz - 50
800Mhz - 75
I don't use 600Mhz
400Mhz - 125
200Mhz - 125
I don't use 100Mhz

I get pretty amazing battery life and it's quite snappy. CPU Spy is an invaluable tool to use.

Don't forget! REALLY test the phone before "apply on boot" is pressed. Phone can hang while transitioning from charging as easily as it can hang during intense benchmarking. I waited 2 full days of full use before applying my settings for good.

 

[kevincwelch]

lattiboy -- What ROM are you using and what kernel?

 

[lattiboy]

Using ACE rom and Genocide kernel. Bernard a great combo for me.

 

[a_c_s]

I've read a lot about UV-ing and the consensus seems to be bias of heavily undervolting lower frequencies and leaving the higher frequencies closer to stock. I have mine set:

1200Mhz - 50
1000Mhz - 50
800Mhz - 75
I don't use 600Mhz
400Mhz - 125
200Mhz - 125
I don't use 100Mhz

I get pretty amazing battery life and it's quite snappy. CPU Spy is an invaluable tool to use.

Don't forget! REALLY test the phone before "apply on boot" is pressed. Phone can hang while transitioning from charging as easily as it can hang during intense benchmarking. I waited 2 full days of full use before applying my settings for good.

Awesome... Thanks... I was fooling myself yesterday and at -75 on higher frequencies, definitely froze on the charger and required a battery pull... At 1000 and 800 I'm at -50, at 600 and 400, -75, and at 200 I'm -100 and seems stable and snappy... appreciate your feedback and I'm going to do some more experimenting today...

As an aside, if any chefs are reading this thread who do their own kernel work, curious what settings you include in your included kernels? Are you pushing harder than what's listed above, or are you more conservative?

Thanks to those who've responded to this thread... it's been a great help and will hopefully help others experimenting with custom undervolting for the first time...

 

[scoob]

Enjoy, OC and UV definately makes my Epic better then stock.
That and custom ROMs may actaully make me content to hold off on getting a new phone this summer... maybe

 

[a_c_s]

Question for the lower frequency tweaking... tried CPU Spy to look at frequencies used, and I spend a lot of time in "deep sleep" mode... in Voltage Controller, I only have 1000, 800, 400 and 200 enabled... 1400, 1300, 1200, 1120, 600, and 100 are not used...

I guess my question is what does "deep sleep" mean? The lowest frequency I use is 200 and that is undervolted to -125 and working fine... I don't know if the system runs below 100mhz frequency... is that "deep sleep"? I just want to make sure I'm undervolting the state in which my phone clearly spends a lot of time...

Thanks for input from any of you voltage tweakers... not that it matters, but I'm on Bonsai 4.0.1 and Genocide 1.0... Thanks

 

[bgdpmp79]

My settings are:

1000 -75
800 -75
600 -100
400 -100
200 -125

I have been running this settings stable for a month now. The battery life is definitely longer when compared with a non-UV setup. I think the "deep sleep" is when the screen is off and in idle mode. So you'd be at the 200MhZ step. You'd have to run a script or something to activate the 100 but a lot of our phones have trouble waking at that speed. My settings are conservative, I think. There are few guys on XDA say they are stable at -100 on 1000 and -175 on 200, but as I said I know mine works for me.

 

[a_c_s]

My settings are:

1000 -75
800 -75
600 -100
400 -100
200 -125

I have been running this settings stable for a month now. The battery life is definitely longer when compared with a non-UV setup. I think the "deep sleep" is when the screen is off and in idle mode. So you'd be at the 200MhZ step. You'd have to run a script or something to activate the 100 but a lot of our phones have trouble waking at that speed. My settings are conservative, I think. There are few guys on XDA say they are stable at -100 on 1000 and -175 on 200, but as I said I know mine works for me.

That would make sense except for the fact that CPU Spy lists me at 9% at the 200 level and then over 80% in deep sleep, implying that there is a step lower than 200 where my phone idle's a lot despite the fact I unchecked 100 in Voltage Control... that's what's confusing me right now...

 

[fab5valentine]

Google CPU Spy and go to the XDA thread. He will explain why he put deep sleep in the update.

 

[bgdpmp79]

Yeah, on post #19 of CPU Spy v0.3.0 on XDA's app and games forum, it explains the reasoning behind it.

 

[a_c_s]

Gotcha... so if I'm reading that right, then there's nothing you can do about "deep sleep" mode as it probably draws little power to begin with...

For the record, this is my current setup on Genocide and running fast and stable:

1000 = -50
800 = -75
600= -75
400 = -125
200 = -150

 

[TexasEpic4G]

This Is Really Helpful

Glad I found this thread = it has been very helpful. When I've asked other folks I usually just get the standard , "you have to try different settings and see what works for your phone" ; which is TRUE but at least here you guys have been kind enuff to show the settings that work for you so those of us who are new to UV can at least get an idea of what to try = THANKS Again !

 

[scoob]

Besides CPU Spy, I have been playing with "Elixir" app which has a nice Widget to monitor CPU frequency and CPU load along with a slew of switches for free.

 

[a_c_s]

Guys, question... I'm testing out the new Bonsai ROM (B38 beta) and the kernel that comes with it, which uses the Smartass Governor... If I understand, the SA gov has more to do with managing frequencies, particularly during down times for better efficiency and battery life... but I have not read anywhere that it does anything in terms of undervolting... so should this work OK with Voltage Control if I want to layer on undervolting to what SA already does, or would it interfere? I was previously using Genocide kernel so SA was not a concern... Thanks

 

[scoob]

I'm runnig the same ROM and had the same question you have.
I've been using Voltage Control with

1120 -0
1000 -25
800 -50
600 -75
400 -100
200 -100

and not using 100.

It seems to work for me but anything higher will lock up my phone. It seems to make the phone last longer but I havent actaully made an timed the batter life, etc...

Anyone else with opinions on how their set up is with Bonsai?

 

[tnuts]

running ACE 2.0 and Genocide 1.0, currently set as follows:

1200 -25
1000 -50
800 -50
600 -75
400 -75
200 -100
(any not listed are not used)

seems to be working like a champ so far. multiple smartbench tests and no issues coming off the charger. i am having an issue with quadrant tho, any time i try to run it it seems to freeze on "CPU- video decoding- H.264". i'm not sure if this is indicative of problems with the settings (although they seem pretty conservative considering what some others are running), or an issue with the program, but until something else starts giving me the business i'm going to roll w/ it

 

[tjnoel2]

I've read a lot about UV-ing and the consensus seems to be bias of heavily undervolting lower frequencies and leaving the higher frequencies closer to stock. I have mine set:

1200Mhz - 50
1000Mhz - 50
800Mhz - 75
I don't use 600Mhz
400Mhz - 125
200Mhz - 125
I don't use 100Mhz

I get pretty amazing battery life and it's quite snappy. CPU Spy is an invaluable tool to use.

Don't forget! REALLY test the phone before "apply on boot" is pressed. Phone can hang while transitioning from charging as easily as it can hang during intense benchmarking. I waited 2 full days of full use before applying my settings for good.

What app are you using to undervolt?