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i7 7700k temps vs RAM speed on z270 mainboard

32K views 69 replies 24 participants last post by  lieshout 
#1 ·
Hi there,

I've bought a new shiny i7 7700k + MSI Z270 Gaming M5 and there's one thing that makes me crazy...

  • My current setup is stable 4.7Ghz on ~1.25V + 2 x 8GB of dual channel G. Skill DDR4 Ripjaws V 3200Mhz (with X.M.P.).
  • I manually changed X.M.P default DRAM voltage from 1.36 to 1.32.
  • I've set -2 to AVX offset (I like this one).
  • IO and System agents voltages: changed auto values to manual (mainboard sets some crazy high values, like more than 1.3), a bit higher than default ones.
It's stable (by stable I mean one hour of realbench stress test and some prime95 26.6 tests).

The problem are temperatures. I use a Thermalright Macho Rev. B air cooler. The temps are reaching 82C average after few seconds of realbench stress test (with max of 87-88).
It's obviously too high. New versions of prime95 (I know, AVX) can go to 100C.

Now, the weird thing: when I set my RAM to stock clocks (2133Mhz), everything's getting normal. Realbench stress tests don't go over 75C, averaging with ~72C.

I've got no idea what's the problem. DRAM voltage doesn't matter in this case. I can go from 2133Mhz to 2400 (without XMP) and the temperatures are the same as in X.M.P. 3200Mhz profile.
Is this possible that my MB raises some inner/hidden voltages (i.e. integrated memory controller, which is inside CPU)?

Anyone, something?
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#3 ·
In UEFI, compare VCCIO & System Agent voltages
Or in windows, check IMC & VCCSA voltages using HWINFO64
 
#4 ·
Well, update.

It appears that higher RAM speed raises the PLL OC voltage from 1.2 to 1.3.
Setting it to default fixes high temperatures (witcher 3 - under 50 degress, before it was over 60, new Prime95 small FFT - max 87 degrees, average of 82-83).

But now there's another thing. The system is pre-stable even on PLL 1.15V. With 1.15 I get some strange results. One of my cores get's 12C on idle.... ????? It's obviously some failure, but the most weird thing is that it doesn't perform worse (in terms of Mhz or benchmark scores). Cores #2 and #3 (last two) are almost 10C colder than first two when using prime95.

Now I'm just confused;)
 
#6 ·
Well, these are my current OC settings:




The system is stable (8 hours of realbench + 2 hours of intel extreme tuning utility). Average temps after 8 hours of realbench are something like:
  • Core #0 - 70C
  • Core #1 - 77C
  • Core #2 - 65C
  • Core #3 - 65C
It appears that my two last cores are colder or the sensors are showing wrong temps (that would explain this 12C case from my last post).
Core #1 seems to be the hot one. I presume it can be intel's "fault" (i reseated, cleaned and used the thermal compound twice; no change, it gets hotter in every stress test I made).

Anyway, the temps before tweaking PLL voltage and those SA and IO voltages (instead of leaving it auto) gave me ~10C less on load.
 
#8 ·
I have the same issue. I manually changed the VCCIO and system agent, and changed the PLL in the only place I saw to 1.0(and even .9 which is said is standard) and it made no difference. All I did here between these 2 was go from auto to XMP, and I already had the IO and SA voltages manually set.

2133 memory temps: Max 73-71-71-72 Avg 65-67-64-65
3200 memory temps: Max 77-77-78-78 Avg 69-70-73-71

That 3rd core is averaging 9 degrees hotter! It goes from the coldest on average to the hottest. I'm also delidded.

2133 memory


3200 memory
 
#11 ·
#12 ·
Quote:
Originally Posted by jasjeet View Post

CPU PLL?
I will test on my Asus z170 later.
Quote:
Originally Posted by ru7hl355 View Post

Does anyone know what / where this setting is on a Asus z270 strix?
Quote:
Originally Posted by Rampage24 View Post

I can only find PLL in the Tweaker's Paradise section. It didn't matter for me though if I leave it auto or set it to 1.0 or whatever.
The setting to change the PLL OCs voltage that you're seeing in HWiNFO64 is located in Extreme Tweaker / Tweaker's Paradise / PLL Bandwidth. It is auto by default, but settings 0 through 3 should reduce that voltage substantially. Adjust as needed.

Hope this helps.





 
#14 ·
Quote:
Originally Posted by Rampage24 View Post

Those aren't in there in my bios. I had a picture of my bios in that section in the last page. It cuts off at the Interal PLL voltage in your screenshot. Does our board not have the option to change that?
I'm using a ROG Maximus IX Formula so I may have some adjustments that you don't. If so, that sucks as that's the one that changed PLL OC for me. I now run mine right around 1v and am happier with it.
 
#15 ·
Quote:
Originally Posted by done12many2 View Post

I'm using a ROG Maximus IX Formula so I may have some adjustments that you don't. If so, that sucks as that's the one that changed PLL OC for me. I now run mine right around 1v and am happier with it.
Is that CPU PLC OC voltage in HW info? If so mine is 0.328 in that.

 
#19 ·
I also have the 7700K with MSI Z270 Gaming M5 mobo. I've been running XMP at 3200 from the day one, so didn't notice the change that OP described. However, after I went to the BIOS and changed all those 3 lines related to PLL from Auto to the default values, my average core temperatures dropped by 6-7 degrees while running IBT at Maximum setting (my memory is still at 3200MHz 1.35V). Interesting.
 
#20 ·
Yes, it seems it's that PLL OC voltage. 6-7 degrees is a lot when it comes to numbers over 80.

The weird thing I don't understand is that getting this voltage lower (i.e. from default 1.2 to 1.15) enlarges the temp differences between my first two cores and last two cores (without performance loss of course).
 
#21 ·
I too have had interesting results with my 7700k MSI z270 m7 board. I lower the CPU PLL OC from AUTO / DEFAULT 1.20 to 1.10 and drop 8-10c. Not sure how this works. The lower temps seem wrong as they are lower than my ambient in some cases. When stress testing they hit 70c before 81c max.... very confused lol... also if I turn on Adaptive and Dynamic CPU even with C1E cannot get system to show drop in core speed or volts anymore. Sits at 1.258v and 4.8ghz all the time in windows. Is this bad? :s
 
#22 ·
If it comes to dropping core speed: maximum/high performance power plan set in windows can prevent dropping. Check this out.

And the CPU PLL OC thing... Really don't know. I's madness. Real madness. I updated my BIOS to 1.4, set everything on auto with 4.7Ghz.
Results? Mainboard sets 1.41 vcore. ***???? 100 degrees with realbench. CPU PLL OC set to 1.17 -> almost everything goes back to normal.

Don't know what MSI was thinking. It's just radiculous.
 
#23 ·
BTW. I got stable 4.7Ghz with 3200Mhz RAM with 1.26 Vcore.

Voltage mode: adaptive
CPU SA Voltage: 1.15
CPU IO Voltage: 1.1
PLL OC Voltage: 1.17
PLL SFT Voltage: 0.9
ST PLL Voltage: 1.0

Stable means: 3 x 8 hours of realbench, few hours of prime95 blend, memtest, intelburntest etc.
 
#24 ·
Quote:
Originally Posted by mimosky View Post

BTW. I got stable 4.7Ghz with 3200Mhz RAM with 1.26 Vcore.

Voltage mode: adaptive
CPU SA Voltage: 1.15
CPU IO Voltage: 1.1
PLL OC Voltage: 1.17
PLL SFT Voltage: 0.9
ST PLL Voltage: 1.0

Stable means: 3 x 8 hours of realbench, few hours of prime95 blend, memtest, intelburntest etc.
Anymore info on if the temp drops are real lol .. still seems too good to be true something is going on with that PLL OC volt drop.
 
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