i5 6600k overclocking temps

Temps are fine. Anything above 75C is where you should get concerned for 24/7 use.

The core voltage should still drop to idle so long as you didn't disable intel speedstep. It may be labeled eist in the bios.

You need to use adaptive voltage or offset voltage if you want the voltage to drop when it's idle

Adaptive voltage shouldn't have to be used. Under power options in the control panel, is it set to 100% all the time? Check to see what the minimum state is set to under processor power management in the advanced options and try setting it to 5%.

I tried it just now, speed step enabled and balanced control plan, my voltage wont lower only frequency lowers.
as soon as i use my adaptive voltage settings. it lowers the voltage and frequency

Your temps are not critically high but admittedly still a little on the high side. With a budget single fan air cooler I stay below 75 C (Prime95 heat test) at 4.6 GHz but at VCore 1.355 V (up to 1.356 V max according to CPUID HWMonitor), which is quite a bit more than your 1.328 V. Using liquid cooling you should be able to achieve better than that IMO. It might be worth adding a fan moving the air better over the VRM for example to get at least an 8 C drop. However, it is not absolutely necessary.

Still, the cooling setup is particularly important, as the amount of power supplied to the CPU is roughly the same as the amount of power that has to be dissipated by the cooler. Power consumption and temperature increase linearly with clock frequency and exponentially with voltage. Have a look here for the fans: https://postimg.org/image/3t7g3ljjt/

By the way, if you want to overclock your Kingston memory, have a look here (I got mine from 2133 MHz to 3200 MHz):
http://hw-db.com/memory/2687/hyperx-hx421c14fbk2-16-review/2

I am having a similar issue with getting my voltage to drop with speedstep (and c-states) activated, but for me it's on a gigabyte board. I will start a new post so I don't hijack this thread.

Relating to temps. I had a stable 4.6Ghz at 1.290Vcore (1.284 CPU-Z) with XMP Profile 1 enabled (Corsair Vengeance DDR4 3000MHz). 3 hours OCCT LINPACK passed, 3 hours OCCT CPU large passed, but temps started exceeding 80 while running OCCT CPU Small. I used the "Relax OC" memory enhancement and my temps dropped 10 degrees and I passed all three tests. Not sure what "Relax OC" does (and can't find any issues) but BIOS shows the same DRAM voltages and timings when I have "Relax OC" on.

PC Specs:
MOBO: Gigabyte Z170 Gaming 3
CPU: i5 6600k
CPU Cooler: EVO 212
RAM: 16GB Corsair Vengeance DDR4 3000MHz
GPU: Gigabyte GTX960OC 2GB

Relax OC basically takes a kit lets say 3000mhz with 15-15-15-35 timings and makes it 3000 mhz with 16-17-17-40 timings. It makes it a decent amount slower but will still run you at that bandwidth.

This thread is OK IMO - 6600K overclocking temps - no need to issue yet another dedicated thread because in the end the temp gets affected by this too...

For your voltage to drop and for the CPU to slow down at idle, you must have Speedstep enabled (it is by Default), but also in Windows, your Power Plan must be set to "Balanced". The "Performance" plan disables Speedstep and uselessly keeps everything max. running which is effectively wasteful and unnecessary as the full performance is given back instantly when needed. Try this and let me know. It should fix the problem.

Your memory kit is fitted with a special chip which keeps in store the JEDEC official tables of working timings. The motherboard will default the memory kit to the chip’s JEDEC timing presets regardless of the XMP profile, so there is no point in loading the XMP profile, better disable it even.

"Relax OC" renders all the timings you have set very loose (i.e. "relaxed" to prevent booting problems), but without showing you the result of this action which can also severely downgrade the overall performance of your memory kit. So, instead of "Relax OC", leave the Memory Enhancement parameter on "Normal" to preserve the timings exactly as you set them. Here are the settings:

Extreme Memory Profile (X.M.P.) = Disabled (if the kits' JEDEC chip provides the table of timings to the mobo)
Memory Enhancement Settings = Normal (to use the settings exactly as entered in the BIOS, not being altered)
(note that the above Memory Enhancement Setting of "Normal" may not be possible (you may absolutely need "Relax OC") and if at all possible, it may greatly increase your temps (by up to 10 C) - better avoided unless you have extreme cooling on tap.)

I also recommend the following:
CPU EIST Function = Enabled (this is Speedstep – good to reduce temps at idle – both GHz and Volts)
For C-States:
CPU Enhanced Halt (C1E) = Disabled (= C1 Enhanced) - (primitive version of Speedstep)
C3 State Support = Disabled (check that the voltage still drops at idle)
CPU C3/C7 State Support = Disabled (not so useful)

Yes and it's not easy to determine exactly what the resulting changes of "Relax OC" are (you could be forgiven to believe that you still use all your very own settings - nothing shows otherwise).

By "bandwidth" (the quantity of data that can be transmitted in a fixed amount of time) you probably mean "frequency" here. The Relax OC 'slows down' the data processing (address, access, read, write, etc.) functionality of the memory kit (i.e. its performance).

Ah, yes philipew. I will check this tonight. I remember that the Samsung SSD installed a “Samsung Performance Profile” and that is what it is set to. (Though I thought I remember vcore dropping when I did a baseline before oc’ing. Again- I’ll check this tonight.


If I DISABLE the XMP profile my memory will run at 2133MHz, 1.2V, 15-15-15-36, whereas if I enable XMP it will run at 3000MHz, 1.35V, 15-17-17-35. (as verified in CPU-Z). Wouldn’t I want to have XMP enabled?


Ok. I didn’t see any changes to the timing within BIOS but I’ll have to see what CPU-Z is reporting when I have “Relax OC” enabled.


Thanks for all the info philipew I’ll give these a try tonight.

Maybe your Corsair Vengeance kit doesn't have the JEDEC memory table chip fitted on my Kingston HyperX Fury memory kit to override the XMP. No big deal to keep it on then... ;-)

I don't think that CPU-Z (or even IBT) will accurately detail the set "Relax OC" timings, but it's worth investigating. In general, the tighter the timings (like a low CAS value for example), the better the performance of the memory kit because these timings are latencies, delays (as you know, 15-15-15-36 is better than 15-17-17-35). The most important factor though is the operating frequency (3000 MHz in your case). As such, going to 3200 MHz would bring a worthwhile performance improvement. But I don't know if your particular kit can run at 3200 MHz.

For the primary timings (CAS, tRCD, tRP and tRAS) like 15-15-15-36, the minimal stable values depend primarily on the memory frequency with voltage playing a secondary role in the borderline areas. However, on Skylake you also have to keep in mind that tRCD must be equal to tRP at all times and that the minimal tRAS value one can set in the BIOS is 28.

By the way, a 1:1 CPU/Cache ("Uncore") frequency ratio tends to raise the temp a little, but also slightly reduces memory latency (1 to 4 %) the higher memory freq. goes above 2133 MHz (2133 - 2333 - 3000 - 4000 MHz). Given your good temps, you could also set it that way. For 4.6 GHz it would then be CPU / Uncore ratio at 46/46 (same multiplier). The Uncore ratio remains at its stock value of 3.5 GHz (i.e. a 1:1 ratio to start with) if you don't manually change it in the BIOS.

For my 4.6 GHz profile I have a CPU / UNCORE ratio of 46/45. I have another post regarding Gigabyte Offset voltage that has all my OC settings listed.

Thanks again - philipew. I will check to see what CPU-Z shows for mem timings in each setting, though if I want to keep 4.6 GHz I need to use "Relax OC" when using XMP to get 3000MHz or my temps go too high. There is a 10 degree difference between plain XMP and XMP with "Relax OC" enabled.

You are welcome - every situation is different as there are so many parameters involved.

"Relax OC" does not modify the memory timings that YOU set in the BIOS but rather values (settings) of the IMC (Integrated Memory Controller) parameters (like the write recovery time tWR, the refresh cycle time tRFC, etc.) located inside ("integrated") the CPU to "ease" (or simply make possibe in your case), its management of the flow of data going to and from the computer's main (RAM) memory under YOUR own BIOS timings (by increasing latencies, etc.).

Otherwise it is much harder (if possible at all), hence the much increased resulting temp that you experienced. But with extreme cooling (e.g. liquid nitrogen), some rigs can afford it (I can't either, unless of course by considerably reducing the operating frequency, like going down from 4.6 to 4.0 GHz, which defeats the OC effort as a whole). Now at least you can understand better why it has to be that way...

These settings might be visible via CPU-Z although they don't really mean much to most people, and you really have to know what you are doing to modify any of them as it becomes highly technical. BTW, not all motherboards allow you to manually change the IMC settings in the BIOS. My Gigabyte GA-Z170XP-SLI does allow it (surprisingly it even carries all the same OC setting as more expensive boards such as the Z170X-UD5).

As you mention, "CPU / UNCORE ratio of 46/45" is fine but "46 / 46" is even (a little) better and wouldn't raise your temp much at all (something very easy to try). Everything counts IMO.

It's all good, enjoy your OC and take care ;-).

I looked at CPU-Z but it only show the freq, voltage, CL, tRCD, tRP, and tRAS but not the IMC (Integrated Memory Controller) parameters. Which is fine - because I wouldn't know how to adjust them anyway - nor do I know if I could make any improvements.

I did verify in CPU-Z that with "Relax OC" set, I do keep the same mem freq, DRAM voltage, and CL / tRCD / tRP / tRAS timings while keeping my temperatures 10 degrees cooler.

Good on you ;-)
Here are my current, and ultra stable, BIOS settings for i5 6600K on Gigabyte GA-Z170XP-SLI:
[1] - CPU Core Ratio: 46
[2] - FCLK Frequency For Early Power: 1 GHz
[3] - Uncore Ratio: 46
[4] - CPU Flex Override: Disabled
[5] - Intel Turbo Boost Technology: Disabled
[6] - CPU Enhanced Halt (C1E): Disabled
[7] - C6/C7 State Support: Disabled
[8] - C8 State Support: Disabled
[9] - CPU Thermal Monitor: Enabled
[10]-CPU EIST Function: Enabled
[11]-Voltage Optimization: Enabled
[12]-Residency State Registration (RSR): Disabled
[13]-Hardware Prefetcher: Enabled
[14]-Adjacent Cache Line Prefetch: Enabled
[15]-Extreme Memory Profile (X.M.P.): Profile 1
[16]-System Memory Multiplier: 32
[17]-Memory Enhancement Settings: Relax OC
[18]-Channel Interleaving: Enabled
[19]-Rank Interleaving: Enabled
[20]-CAS Latency: 15
[21]-tRCD: 17
[22]-tRP: 17
[23]-tRAS: 28
[24]-Command Rate (tCMD): 1
[25]-CPU VCore Loadline Calibration (LLC): High
[26]-CPU VCore: 1.355V
[27]-CPU VCCIO: Normal
[28]-CPU System Agent Voltage: Normal
[29]-PCH Core: Normal
[30]-DRAM Voltage (CH A/B): 1.360 V
[31]-Internal Graphics: Disabled