Underclocking and volting while ability to have turbo on i3-4130, dream or reality?

[stuff_me_good]

So I went and bought i3-4130(3.4-3.7GHz) processor instead of the T(4130T)(2.9-3.3GHz) model. I was planning to underclock and undervolt it, but then I realized that do I loose turbo in the process?

Underclocking and volting with fixed settings is easy, but in the process you loose turbo and power saving, because you always have the same fixed clocks.

What I want is that, when I underclock for example 4130 default 3.4ghz to 2.6ghz and still have for example 3.2ghz for turbo. So I'm guessing there has to be some setting in the bios for setting two set of clocks, one for base clock and other for heavy load locks. Is that possible?



My scenario now in the current state would be that my 4130 processor has default clock of 3.4ghz and I want to have it idling around 2.6ghz. But the problem is that when I have all the power saving features on, does the processor overclock itself from my own adjusted 2.6ghz to the processors actual default clocks 3.4ghz? Basically I have to have the ability to set my own underclocked default clock and my own underclocked turbo clocks.


Do I make any sense? :hmm:

 

[lyssword]

i think turbo clock is separate in bios from normal clock

 

[Blastman]

Underclocking and volting with fixed settings is easy, but in the process you loose turbo and power saving, because you always have the same fixed clocks.

Yes, but the multiple power saving features on modern CPU's since Core2 are so good that you will probably save a negligible amount at idle by underclocking and undervolting.

On my i3-530, I have the CPU undervolted to 1.01v (from default/stock ~ 1.18v). At default with speedstep on, my i3 drops to a 9x multiplier = 1.20Ghz (from 22x under load = 2.93Ghz) and drops the vcore to 0.94. When I set the vcore manually to 1.01v speedstep is disabled so my CPU stays at 2.93 and 1.01v all the time.

Under load and undervolted my temperatures drops a lot compared to default settings.

While idling undervolted (2.93Ghz/1.01v) my temperatures are within 1.0C of what it was when speedstep was on with the CPU dropping to 1.20Ghz/0.94v. This is with stock Intel HSF. Almost no difference. During idle, even at 2.93Ghz, my CPU consumes hardly anything more than at 1.20Ghz.

My results suggest that undervolting and underclocking will mainly help you under load and will not do much at idle.

You might try leaving your CPU at stock speeds and just undervolting. You might have to turn off turbo if your vcore gets close to minimums.

 

[BSim500]

i3's don't have Turbo Boost, and the i3-4130 has a fixed maximum load speed of 3.4GHz (as did the older i3-3240):-
http://ark.intel.com/products/77480

What happens with the T chips is that the 2-thread load multiplier is *lower* than regular stock default (not the 1-thread load that's higher) in order to cap the max TDP at any given time. That's similar to (but not the same as) "Turbo Boost".

SpeedStep auto-under-clocks & under-volts anyway across a range of intermediate steps according to load (800Mhz idle -> 3.4GHz load), so there's zero point in manually clocking the chip lower because it does it transparently anyway on both chips.

Eg, on my i5-3570 (non-K), the SpeedStep steps are:-

1.6GHz @ 0.680v (full idle)
2.2GHz @ 0.728v
2.6GHz @ 0.768v
3.0GHz @ 0.832v
4.0GHz @ 1.006v (stock voltage OC)

i3's still have the same Speedstep and work the same way, you just can't go past 3.4Ghz (no Turbo Boost). So you're actually crippling performance by manually setting it lower as with SpeedStep enabled, it'll transparently auto-under clock & volt it to say 2.2Ghz or 3.0Ghz or all the way down to 800MHz idle as needed according to load for the maximum in power savings anyway. It's not something you have to manually tweak anymore.

And if you have a Z87 board, you can still manually undervolt with a negative offset (WITHOUT underclocking) resulting in a lower TDP all round. You're not losing much by not getting a T chip. I can knock off over -0.12v of my i5-3570 at stock 3.4GHz turning a 77w chip into one that barely draws 45w load 4-threads loaded Prime resulting in cooler operation than an i5-3570S chip at stock. That's often how much headroom they have.

What you need to do is set the default multiplier back to 34 (3.4GHz), leave SpeedStep enabled and simply undervolt it as far as you can (do stability testing), which will have the effect of lowering TDP across ALL voltage states, idle & load. This will give you the absolute lowest TDP (often even lower than a stock untweaked i3-4130T chip) without losing 30% of your performance (as you are currently doing by fixing it at 2.6GHz).

 

[stuff_me_good]

Oh yes, thank you BSim500, I completely forgot that intel speedstep is already underclocking and volting the processor during idle.

I completely forgot that, in ivy bridge the idle clocks are 1600mhz and haswell goes as down as 800mhz. And you are right, I don't want to cripple the maximum load performance by clocking it down to T models speed, but rather I can even overclock it a bit. Even then the processor would go back to 800mhz clocks when idling, which it is going to do mostly anyway. Or I could just let the processor stay at default clocks and like BSim500 said, just offset undervolt it a bit so it will be more efficient across the board.

Not sure though, would the offset undervolt affect on the idle volts also? For example if the idle clocks are 800mhz and voltage 0,8v. Load clocks would be 3400mhz and voltage let say 1.2v and I offset undervolt it -0.05v, so load voltage would be 1.15v. Would it affect on idle the same amount, in this case make it 0.75v on idle?

 

[BSim500]

Not sure though, would the offset undervolt affect on the idle volts also? For example if the idle clocks are 800mhz and voltage 0,8v. Load clocks would be 3400mhz and voltage let say 1.2v and I offset undervolt it -0.05v, so load voltage would be 1.15v. Would it affect on idle the same amount, in this case make it 0.75v on idle?

Hi, yes it will reduce idle voltage by same amount as well (or at least it does on my Asus P8Z77-M), however in my experience Intel chips have a fair bit of headroom across all voltages states. You're better off doing it in small steps (eg, -0.01v to -0.02v) then testing stability, then repeating etc, until you know where the limit is (then back off a little), as each chip is different. "Testing stability" when undervolting means not just running Prime under load but keeping an eye out for "WHEA-Logger Event ID 19" errors in Event Viewer / BSOD's when using the computer for general browsing where the computer will typically spend more time at lower SpeedStep states. I seem to have a nice -0.10v stable headroom with mine (across all steps) even with a mild OC to 4.0-4.2GHz, but others have shaved as little as -0.02v or as much as -0.18v off default clocks, so its trial and error that's often unique to your chip. Best of luck.

 

[Blastman]

Not sure though, would the offset undervolt affect on the idle volts also? For example if the idle clocks are 800mhz and voltage 0,8v. Load clocks would be 3400mhz and voltage let say 1.2v and I offset undervolt it -0.05v, so load voltage would be 1.15v. Would it affect on idle the same amount, in this case make it 0.75v on idle?

Yup as Bsim500 pointed out, idle volts is dropped the same amount as offset.

For example, default with speedstep load/idle …

2.93Ghz … 1.18v
1.2Ghz … 0.94v

If I use an offset of -0.05v …. I get …

2.93Ghz … 1.13v
1.2Ghz … 0.89v

The problem with using an offset is that the lower end limits my offset before the higher speed does. An i3-530 at 1.2Ghz gets close to having stability problems in the mid 0.80v range. So if I try and use an offset of -0.10v, when speedstep kicks in my CPU will try to run 1.2Ghz/0.84v when idle and may have stability problems. It will run 2.93Ghz at 1.08v no problem …

Using an offset of -0.10v …

2.93Ghz … 1.08v … … no problem, stable
1.2Ghz … 0.84v … … this is where the problem lies.

My CPU runs stable 2.93Ghz at 1.01v, equivalent to an offset of -0.17v. With speedstep on and an offset of -0.17v, my CPU won't run when speedstep kicks it down to 1.2/0.77v.

Thtat's why I run 2.93Ghz/1.01v all the time. I get better (lower load) temperatures by having the lowest vcore at 2.93Ghz. At idle, the power saving features are so good that I don’t use much more power than if I was using speedstep. Under load is where small adjustments in vcore can make a big difference.