2600K idle voltage - something seems goofy with mine

[Idontcare]

New setup here - 2600K on a Maximus IV Z

My 2600K idles at 1.25V, which seems a little high, and drops to 1.168V during LinX which I expect based on Vdroop considerations.

The 2600K idles at 1.6GHz, when I run LinX it runs all cores at 3.8GHz (cooling here is with a H100).

I would have expected the idle voltage to be much lower, around 1V or so.

Everything is stock default on this thing. BIOS is all defaults, windows is all defaults, nothing has been tweaked or changed on this setup yet.

Do I need to change something to have my idle voltages drop?

 

[mmaestro]

Sounds like it. My 2600K idles at 1.6Ghz, and a hair under 1V. Sounds like you have a fixed voltage set and nothing turned on to compensate for the Vdroop.

 

[Idontcare]

OK, that confirms my suspicions, thanks for the sanity check :thumbsup:

Now I need to figure out why my mobo is doing this by default. I would have though LLC would be default these days and letting the CPU drop its idle voltage would be default as well.

 

[john3850]

LLC is almost becoming your new vcore.

 

[mhgsx]

I'm running the same board and chip combo. I don't know why Asus has the MB default that way, but I noticed that, too, when I first built my rig and it took me forever to figure it out.

Did you also notice that it defaults to max turbo across all four cores, instead of using the designed turbo modes of Intel?

You have to enable "offset" mode to utilize the voltage ramping. Can't remember which OTHER setting I had to manipulate to enable offset mode as an option. Pretty stupid to have to perform 2 steps, but what the hell do I know.

 

[Idontcare]

I'm running the same board and chip combo. I don't know why Asus has the MB default that way, but I noticed that, too, when I first built my rig and it took me forever to figure it out.

Did you also notice that it defaults to max turbo across all four cores, instead of using the designed turbo modes of Intel?

You have to enable "offset" mode to utilize the voltage ramping. Can't remember which OTHER setting I had to manipulate to enable offset mode as an option. Pretty stupid to have to perform 2 steps, but what the hell do I know.

Yeah I was going to post about this, been fighting internet issues though.

Here's what we Maximus IV Extreme-Z owners have to do to change the defaults in Bios 403 so that our CPU will be allowed to automatically reduce its voltage when idle:

The "goal" is to change the CPU Voltage bios setting from its default "Manual Mode" to the alternate which is called "Offset Mode". To do this though we must first pay a visit to the "Digi+ VRM/POWER Control" sub-menu.

Step 1:

Step 2:

In order to convince the ASUS Bios to let us change CPU Voltage to Offset mode we must first change the VCore Phase Control setting to anything other than its default value (which is the EXTREME setting)

Step 3:

Step 4: For the purposes of the topic, it doesn't matter whether we choose optimized or standard here.

Step 5:

Now we are allowed to choose the "Offset Mode" for CPU Voltage, no other changes are required at this point.

This is true if you use the "Advanced Setup" menus. If you are using the "EZ Mode Setup" BIOS then there is no way for you to make these changes.

 

[mhgsx]

When I was messing around with Offset mode to get the idle volts down, I noticed that by leaving the "+/-" offset field to auto, I would get really high volts @ 4.4 or 4.5 Ghz. Something in the order of 1.35-ish volts.

Of course, the temps would be sky-high. So playing with this, I ended up using a negative offset of -0.055 to lower my volts down to 1.272-1.280 using Prime 95. However in IBT, the volts would fluctuate from 1.258 to 1.296 (stress @ max, threads =4) Seems like the fluctuation is a bit high for my tastes. (running @ 4.5 using the same settings would sometimes BSOD)

Over the past hour, I've been stress testing and logging temps using offset mode and the settings I have listed @ 4.4 ghz ambient temp= 24C
idle temps: 34C (0.91 volts)
IBT temps: 82C (1.258v to 1.296 v)

I read about the possibility that manual mode would run cooler with less fluctuations. I set the vcore to 1.265 v, but I get a decent amount of vdroop.
idle temps: 38C (1.265 v)
IBT temps: 77C (vdroop down to 1.232 - 1.248v)

The temps are obviously lower due to the lower volts from vdroop. But, the volts are more steady. Kinda surprised that I didn't BSOD with these volts. Gonna run again with some LLC to see if I can get the volts up to 1.265 and check temps.

Update: vcore set to 1.265v, but cpu-z reads @ 1.272v
idle temps went down to 36C while I was typing.
LLC was set to 50% correction.

 

[mhgsx]

Set LLC to 75% and @4.4 ghz, volts went to 1.264 - 1.272 in cpu-z using IBT. Temps went up to 80C.

I tried bumping up to 4.6ghz, then lowering down to 4.5ghz but all I got were BSODs as soon as I tried to run IBT. Volts stayed the same as above.

I know my chip can run at least 4.5 ghz, since it was stable at anything over 1.3x volts, but the temps were too high for my taste. We'll see if there's any improvement when the GT15s come in.

For now, I'm gonna leave it at 4.4 ghz, but using a vcore of 1.245 (cpu-z reads 1.248v) with the LLC set at 75%. So far with IBT running, the volts fluctuate between 1.248 to 1.256v. Much better than when I was using offset mode.

 

[Idontcare]

Set LLC to 75% and @4.4 ghz, volts went to 1.264 - 1.272 in cpu-z using IBT. Temps went up to 80C.

I tried bumping up to 4.6ghz, then lowering down to 4.5ghz but all I got were BSODs as soon as I tried to run IBT. Volts stayed the same as above.

I know my chip can run at least 4.5 ghz, since it was stable at anything over 1.3x volts, but the temps were too high for my taste. We'll see if there's any improvement when the GT15s come in.

For now, I'm gonna leave it at 4.4 ghz, but using a vcore of 1.245 (cpu-z reads 1.248v) with the LLC set at 75%. So far with IBT running, the volts fluctuate between 1.248 to 1.256v. Much better than when I was using offset mode.

Your idle volts are so much lower than mine. lowest I've seen is 1.008V idle.

That said, have you tried setting LLC to Auto? I'm currently dealing with a memory instability issue, can't tell yet if it is the mobo itself or the dimms, so I'm not able to explore CPU OC'ing yet.

 

[mhgsx]

Your idle volts are so much lower than mine. lowest I've seen is 1.008V idle.

That said, have you tried setting LLC to Auto? I'm currently dealing with a memory instability issue, can't tell yet if it is the mobo itself or the dimms, so I'm not able to explore CPU OC'ing yet.

My idle volts were that low because I was running a negative offset. It's kinda jacked up that I needed to run a negative offset in conjunction with a LLC boost to get to the volts I wanted @4.4 ghz and still be able to idle so low.

I did set the LLC to Auto in the beginning. That's how I knew it was stable @ 4.5 since setting to Auto caused my volts to go to 1.4-ish volts. Temps were fine as long as I didn't run any stress tests, and the comp didn't BSOD. When I did stress...it would shoot up as high as 89C, but it was rock steady. In the interests of longevity, I started testing the lowest volts I could go.

Do you still have mem issues even if they're set to Auto?