i5-6600K (pre-)overclocking advice

[TheF34RChannel]

This weekend I plan on diving into that BIOS and overclock my i5-6600K. I'm aiming for 4.5GHz - 4.75GHz. Before I start, I'm sure I have to learn a couple of things and I've been reading up on it a bit and will continue to do so - however some handy quick tips from your guys won't hurt. I'll leave the BCLK alone for now.

- Could I aim for 4.5GHz without changing voltages, or would it be pointless from the get-go?

- What are safe max voltages & temps (approximately) for the CPU? (The hottest I've had on stock clocks after a gaming session is 45 degrees Celsius).

- Are there any other voltages I (might) need to fiddle with (including load line calibration levels)?

 

[Kilbane]

First off dude, don't go into overclocking with a target in mind. Take your time to learn what your chip likes/dislikes. First thing to do is make sure your voltages are set manually. Start with increasing the multiplier to find where your chip stops being stable. If you still want to go higher start to increase the voltage in small increments. Personally i dont like going above 1.35v (that is in no way a power target to aim for, lowest stable voltage is the aim), but always check the temps under stress. Remember you could get your ideal OC in place then start to bring the voltages down to reduce the heat. A good overclock is all about the speed at the lowest voltage possible. LLC will allow the CPU to use more voltage when needed to help against voltage droops so you don't want too high a LLC level othyerwise its countering the voltage fettling you will be required to do . Always use a good hardware monitoring program so you can see what voltage and temps your chip is running at so you can see what your changes are doing.

Ultimately it is a long drawn out process of back and forth between OS and BIOS. Work slowly with minor changes so you can assess your next change. Stress test as you go. Remember every chip is different, there are no magical settings that will work on all 6600k's.

Good luck with the OC, keep us updated and if you need any guidance just ask.

 

[NeverBackDown]

Instead of aiming for a clock speed, I aim for a volt limit. For example how far can I get the chip at 1.25v. I prefer that way of thinking personally because you could hit the 4.5ghz goal if you wanted but what if it's at 1.35v? That's far too high..

I start at stock clocks and turn off all the power saving functions and turbo boosting(so it's a 24/7 OC) and then find the lowest voltage I can get the chip stable at. Then you would just up the clock in increments then work your way up in volts till you can boot into windows. Just keep going until you hit some clock speed you are happy with then find the voltage it's stable at.

 

[TheF34RChannel]

Thanks guys! I would like to keep power saving settings on for normal use - I use the system as much for typing as I do for gaming and for the former there's no need for an overclock

@ Kilbane: you said voltages; which voltages will I need to set manually and which leave on at auto?

I think I can find out the max voltage it uses for the stock turbo clock with occt and use that as a base.

About the LLC, is this something I need to lower a level? Or, rather, when will I need to lower it or leave it as it is?

 

[MrKambo]

maybe watch this, explains alot of stuff you kinda need to know before jumping in head first, its not for skylake but the fundamentals are similar

 

[Kilbane]

Set your CPU core voltage manually. Use CPU-z to find your voltage. It should be around 1.2v IIRC for a 6600k. Dont set Max voltage that you find under stress as this will be over what your chip need as the BIOS will happily throw extra voltage through your CPU to ensure it is stable.
Leave LLC as it is to start if you prefer, once you have found your multiplier start to knock it down a little to help reduce voltages further. Just think of LLC as a saftey buffer for your core voltage.
The higher you set it the more of a buffer you give the voltage to move e.g setting vcore @ 1.2v on high LLC may give your chip upto 1.3v where as on low it may only give up to 1.21v (not accurate figures but just used to show how the different levels would work).
Dont worry about the other voltages for now.

As you are new to the whole OC part of things it can seem daunting when you first start out. Start simple and the rest will come in time. Multiplier and voltage are pretty foolproof as long as you keep the voltages at a sensible level and keep an eye on your temps.

 

[TheF34RChannel]

Thanks lads!! Kilbane, voltage in CPU-Z shows it changes right now (because of the power saving features, so how do I know which one to take? The one when it's running at full speed but when not under stress?

 

[Kilbane]

It doesn't really matter where you start as it will be changed up or down to make the OC stable. what voltages are shown when CPU-z shows the speed at boost clock? (3.9Ghz IIRC)

 

[TheF34RChannel]

At 800MHz it shows 1.264v (in Windows doing nothing).
At 3.9GHz it shows 1.232v (CPU-Z > bench > stress CPU).

It's lower at the higher speed, I double checked.

For 3.9GHz I'll have to put it under stress, which voltage I wasn't advised to note down earlier? If there's a different, correct way to obtain it do let me know and I'll post back here.

 

[Kilbane]

In that case set your voltage somewhere between the 2, 1.25v will be ample to see a good OC. Go and test it out. Nothing to lose. 4.5Ghz@1.25v will either work or not, if it doesn't boot, start to bring the multiplier down until it does.

 

[TheF34RChannel]

Will do that first and see how it goes. I presume it would be best to stay (way) below 70°C?

 

[NeverBackDown]

70C is fine. I try to keep mine under 85C when using OCCT. As long as it's under 90C i'd say you are ok. If you ever hit 90C then you really should be either stepping down the OC or beef up the cooling solution. That's just my personal thinking though.

 

[TheF34RChannel]

Ran OCCT for 30 minutes: CPU: Linpack, memory 90%, 64 bits. Did I get that right (see screenshot)?

I'm having fun man!


The results.

I went a bit further than you guys suggested because, well, I couldn't help myself! I did this in the BIOS:

Disabled XMP, Re-enabled XMP and clicked No at the prompt ("Would you like to apply the all core enhancement with the XMP settings for improved performance? Select "No" for Intel stock operation. Sufficient processor cooling is required under the all core enhancement") - I admit I'm not sure which setting is best or what the differences are. Saw it in a video and thought, what the heck. Maybe one of you knows? I think it's got to do with enabling manual overclocking for me?

1 to 4 core ratio: 45
Min. CPU Cache ratio: 41
Max CPU Cache ratio: 41
CPU Core/Cache voltage: Manual
- CPU Core Voltage Override: 1.250v (CPU-Z reads 1.264v)
Maximus Tweak: Mode 1
CPU Load-line Calibration: Level 5

Ambient room temp: 21.5 C.

I'm very pleased with the 4.5GHz / 4.1GHz (cache) and I'll stick with it. I have SpeedStep enabled so it clocks down but the cache remains at 4.1GHz; is that a problem? Should I lower the min to auto and leave the max at 41? Why does OCCT say 3.5GHz in the graph, because it's old? Any tips for things I did wrong or can be improved are welcome!

 

[Kilbane]

Good start, try and start to bring the Vcore down now. OCCT and Z170 IIRC dont work well together at the moment. Trust what HWmonitor is telling you. Temps look good.

 

[TheF34RChannel]

Good start, try and start to bring the Vcore down now. OCCT and Z170 IIRC dont work well together at the moment. Trust what HWmonitor is telling you. Temps look good.

I was very happy it worked on my first attempt! Will do man (lowering the Vcore). How big should the steps be?

What about the Min. CPU Cache ratio: 41 / Max CPU Cache ratio: 41. If I want the cache to clock down as well along with the core clock, should/can I set the min to auto? Does it even matter?

 

[Kilbane]

CPU Cache ratio as far as I am concerned makes very little difference in noticeable speed. It can be useful to try and stabilise an OC but personally don't play with it.
Your voltage drops can be done as follows (Not an exact guide but my preferred method):

1.25 > 1.24 > 1.23 etc.
Stability test between each voltage drop. When you get to one that is unstable start upping the voltage again by smaller increments i.e
1.2 (unstable) > 1.21 > 1.22 until stable
then rinse and repeat to get an exact voltage if you want

For a reference, my 4670k is stable at the following

4.5 @ 1.195v
4.6 @ 1.215v
4.7 @ 1.240v

however be aware that temps will increase with larger clock speed and voltage. Just a matter of finding that sweet spot. 6600k should be a better clock/voltage than my 4670k if you have got a good chip (remember silicon lottery is all important, I have a good chip for clock/voltage ratio)

 

[TheF34RChannel]

Good tips, cheers. I should've been more detailed earlier; I mean that currently the core speed clocks down while the cache remains at 4.1GHz (because I set both the min and max at 41). I'm asking if the difference is a problem, and, secondly, if I should set the min to auto to allow it to clock down as well, and, thirdly, if it works at 4.1GHz, can't I just leave it at that (if it works, it works I mean ). Sorry for the confusion.

 

[NeverBackDown]

Having not messed with a Z170 platform I can't say for 100% sure but I don't think you can lower the cache clock like you can with speedstep and the core clock.

 

[TheF34RChannel]

Ah that would be a shame. I read somewhere that the cache should be equal to or lower than the core clock? Which it is under load, but only then. Tried to set the min to auto for the heck of it but it won't; will reset itself to 41. I'll leave it if it isn't harmful to run the cache at 4.1GHz 24/7 while the core clock is under SpeedStep control. Maybe I shouldn't have fiddled with it, but man, it looks so sweet at 4.1GHz

Edit 1:

Went down okay to 1.230v (BIOS), CPU-Z reads 1.232v. Then down to 1.220v (BIOS), CPU-Z reads 1.232v again?

The only difference is that with the former it started at 1.248v on it's own when OCCT started, before quickly lowering to 1.232v, and upped itself again to that higher voltage after the test finished. With the 1.220v (BIOS) / CPU-Z 1.232v setting that doesn't happen and it remains at 1.232v.

Edit 2:

At 1.170v (BIOS) it's unstable and PC restarted upon opening OCCT. Tried 1.180v (BIOS) / CPU-Z 1.184v which was stable (10 minutes OCCT). Tried 1.175v (BIOS), CPU-Z reads 1.184v.

I will run OCCT for 30 minutes now. I think I've found my voltage. Will post a screenshot if it finishes okay for your lads to review settings- and temperature-wise.

Edit 3:

Finished the 30 minute OCCT run. Ambient room temperature = 23 Celsius (yesterday was 21.5 C).

Important bit:

So I've set the Vcore to 1.185v in the BIOS / CPU-Z reads 1.184v, but it starts in idle at 1.200v, before lowering itself to 1.184v after about 30 seconds of OCCT, and goes back to 1.200v after the test, and back and forth at times during the test. It didn't do that when I set 1.175v in the BIOS (CPU-Z reads 1.184v); then it's a solid 1.184v. What would you conclude about this?

 

[Kilbane]

The voltage readings i can only assume that the mobo sees a slight instability at certain points and boosts the voltage with LLC to compensate. @1.175v LLC is clearly already boosting the volts up to 1.184v. Drop the LLC level down and it will probably lower that spike. Personally I would up the Vcore another notch to see if it stabilises. You need to find a voltge that is consistent. Remember you can set LLC to the max and set a Vcore @1.0v, it will just up your voltage to what it thinks it needs (which is generally always higher than it does), that doesn't make 1.0v a stable OC. LLC is great for those random moments a Chip will need a little boost, but dont rely on it to stabalise your voltage.