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How to overclock DDR4 G.Skill 4133 on Asrock Z170 Formula

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New Member
Aug 25, 2016

I'm new here. Although I did work really hard with computers the last 30 years, I never did overclocking. I wanna change this right now.

My System:
Asrock Z170 Formula
Intel i7 6700K (1151)
4 x 4GB G.Skill 4166 25-25-45-19
EVGA Nvidia GTX 950
2x M.2 Samsung 961 256 GB
1x 256 GB Samsung 951
2x Samsung 850 Pro

Asrock says with one memory module it is possible to get the RAM up to 4.500.

But whats more interesting for me:

I wanna get 2 and 4 modules up to the max on this board.

Does anyone know a tutorial, where this is described?

The specs are here


thanks in advance for your support!

Good luck, you're at the mercy of your IMC.

You'll get better gains by overclocking the CPU than the RAM.
Also, honestly, you wasted money by going for that RAM over something that's in the 3000MHz CL15 range.
sorry, my english is still not perfect, whats IMC?

I know, that maybe this RAM was too expensive, but for test purposes it is necessary. At the moment, I need the fastest DDR4 thats available.
Wow... not sure you will be able to get 4 sticks up that high...2 likely if your IMC can handle it (Integrated Memory Controller).

Have you just tried enabling the XMP profile and see if it works? It likely won't. Maybe try to raise SA and IO voltage .1V or so each first. Then try enabling XMP.

And holy crap... 4166MHz.....................CL19??? 19-25-25-45? 1.4V!
Can you also post a screenshot of the Memory tab in CPUz?

What are you doing that you need 4133MHz memory?
tomorrow more, now my wife needs me.

Thank you for wanting to know.

I already was at 4333 but have no proof of that. Will get the proof and raise to 4500. Looking forward to that...
There are no special tutorials how to do it. When you have 4133 memory then simply use XMP profile or use XMP and manually set voltage and main timings if something isn't working right. Z170 OCF is setting optimal timings in most cases when you leave anything at auto. Also you have to set higher VCCSA/VCCIO but I guess that motherboard already set it high.

4 memory modules are much harder to overclock than 2. Also first slots are 2/4 counting from CPU side and in these slots memory is overclocking better.
Even if manufacturer said that this board supports up to 4500, it doesn't mean there are good enough memory modules and that all slots can be occupied.
F4-4133C19D-8GTZ kit was tested in single channel ( 1 slot ) @4500 and dual channel @4133-4333. There is no guarantee that any 4 module kit will run above 4000. On the tested memory list the highest 4 stick kit is 3733.

I had no issues to set 4266+ on any CPU that I had what includes i7, i5, i3 and last week Pentium G4400 on which I passed 4480. However because of architecture, it's hard to stabilize anything above ~4133. It's not because of IMC but because of motherboard design and possible interference.
On 3 different CPUs and 3 different memory kits I have the same max clock. It's or motherboard design or BIOS. Motherboards with 2 memory slots are overclocking better and are easier to stabilize at higher memory clock just because of shorter traces and less interference on the way to CPU and back. For me it's easier to stabilize 4200+ on MSI Z170I Gaming Pro AC than on ASRock Z170 OC Formula. On the other hand the best overclocking Z170 motherboard is Z170M OC Formula so 2 memory slot design with special PCB design to reduce interference.

It doesn't mean that max clock can't be higher but maybe on my motherboard it's the limit. I'm just saying that IMC is stronger than the motherboards. In theory nothing above 3200 is guaranteed but in real I haven't seen CPU which couldn't make 4200+.
@Woomack & ATMINSIDE - Thanks for your replay.

sorry that my answer is late, son was a bit injured, so I had other things to do.

I was researching and developing about increasing computers to highest speed without any overclocking for about 15 months now and the result - as I think and hope - is quite nice:

ashampoo_snap_2016.08uesh2.png ashampoo_snap_2016.08ofse1.png ashampoo_snap_2016.0856sc6.png
my one is the green one - a samsung 850 Pro - the next two also:
ashampoo_snap_2016.08iqogi.png ashampoo_snap_2016.08ykpqi.png

I did run over 8.000 datatransfer- and wholesystem-tests with these benchmarks:

CrystalDiskMark, Atto, Anvil Benchmark, AS SSD, PCMark 05, Vantage, 7, 8, Passmark Performance Test, Roadskil, SSD-Z, HD Tune, Iometer, NovaBench, AIDA...

and I have the result of computers making faster between 50% an 160% - and yep, as said, without overclocking.

And now, as said, I wanna see, what is possible WITH overclocking as cap or keystone of the research

So I want to try to get the G.Skill 4133 up to 4500:

I thougt about these changes:

1. increasing the ratio (correct word?) - no change of timings

Original 4133 2066 CL 19 25 25 45 583 2T 1.40V
Try 1 4266 2133 CL 19 25 25 45 583 2T 1.45V
Try 2 4400 2200 CL 19 25 25 45 583 2T 1.50V
Try 3 4500 2250 CL 19 25 25 45 583 2T 1.55V

2. same ratio, Timings down:

2066 19 25 25 30 583 1T tight
2066 19 22 22 30 278 1T tight
2066 17 22 22 30 278 1T tight
2066 15 22 22 30 278 1T tight
2066 13 22 22 30 278 1T tight

Do you think this method is leading to success? Or do you think some things could be changed at these settings?

the numbers I deviated from this posting: OC of an G.Skill DDR4 3866

http://www.hardwareluxx.de/communit...6-cl18-22-22-42-f4-3866c18d-8gtz-1096344.html (german, but numbers readable without knowledge of german language)

the only problem is, that I am not able to find the change in ram ratio, I only find cpu ratio and cpu cache ratio, at the moment at 42/41. Does anybody know, where it is in the Asrock UEFI?

thanks for your help and sorry for my bad english


- - - Updated - - -


thanks for your reply.

Yes I have tried XMP settings. At the moment, only one RAM is in the ****s of the mainboard.

the original problem is solved, board is working fine with one RAM.

I know, that with only one RAM I can get to 4500, with two I can get to 4333 (Asrocks Info)

I load the XMP profile and start from it with tuning.


  • ashampoo_snap_2016.08uesh2.png
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yes I am trying to put them in an album - is this ok? Sorry, not familiar with writing in forums, I am a lonely benchmarking beast. Deleted all photos already. Are the thumbnails ok?
There's a button at the top of the post window that, when you hover over it, says "Insert Image". This is the easiest way to add images to your post.
thanks, did already use it, will not use attach files anymore, sorry. How can I make a signature? I dont find this pussibility in my profile...
yes I am trying to put them in an album - is this ok? Sorry, not familiar with writing in forums, I am a lonely benchmarking beast. Deleted all photos already. Are the thumbnails ok?

Sorry this is a little off topic but if you enjoy benchmarking have you ever considered joining our benchmarking team?

If you can successfully validate a speed of 4500 on your ram it would be a big help in the current team cup we are competing in. If your interested you can find details in the link below.



Oh, and the signature setup is under the settings tab and is about halfway down on the left. You may need a certain number of posts before it will allow you to set one up.
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will think about that, the next two days benchmarks 20h per day, sry, no time to reply deeper