DDR4 Overclocking with Hynix MFR
So youwant to overclock your fancy new DDR4 kits? Alright well here is some of myexperience that can aid you in your journey and perhaps save you some time.
The RTL Game
This is thebiggest factor of DDR4: RTL
Im no scientist but I do know that the tighter/lower your RTL value is, themore “free” performance or as the latest overclocking phrase (for when youdont have good hardware and you are bored) high efficency. Im not going to boreyou with the science behind it, partly because I have no idea but here are thebasics and some easy extra performance.
RTL is directlyConnected to your tCL(Cas) tWCL and IOL Values.
The lower your tCL and tWCL the tighter your RTL value should be set bydefault.
Forexample:
Cas 16 and tWCL16 will make RTL 61/61/61/61.
Cas 12 and tWCL 9 will make RTL 51/49/51/49.
Heresa chart with optimal RTL value with different tCL and tWCL values.
You can check these against your boards default and make changes accordingly.
Forexample:
Cas 12 with tWCL9 and IOL 8/8/8/8 makes RTL 51/49/51/49.
Cas 12 with tWCL 9 and IOL 6/8/6/8 makes RTL 49/49/49/49.
Lowering IOLvalues will help you to lower RTL and increase your performance.
Sometimes IMCand or quality of the memory will hold your performance back. If this is thecase then you can loosen RTL by forcing a higher IOL such as 8/8/8/8.
What to Buy
So now that weknow about RTLs we can hear some truth about what kits you should target tobuy.
The answer is anything 3000 MHz C15 or higher is your best bet. But on thesame thought, buying 3333 MHz C16 doesnt guarntee you a better kit!
Forexample:
G.Skill 3000 MHzC15 on XMP will set tCL 15 and tWCL 14 which in turn will give you RTLs of57/57/57/57. G.Skill 3300 MHz, CL16, tWCL, 16 RTL will give you RTLsof 61/61/61/61 and G.Skill 3200 MHz, CL16, tWCL 15, RTLs of 59/59/59/59.
All of these are likely to give you similar performance within a second ofeachother on SuperPi 32m.
So its my recommendation to buy 2 sets of 3000 MHz C15 instead of 1 set of3300 MHz C16 for the same price etc.
DDR4 is trickyin this sense. More than ever is it important to find good quality IC’s.
This stems from the fact that at certain frequencies adding extra voltage isnot going to help you but actually hurt your overclocking stability.
Its not like DDR3 MFR that will scale to 2.0+ volts on air. So first we mustfind sticks that run nicely at moderate voltage.
I have tried 4 different high bin G.Skill kits. And all of them have 1sometimes 2 sticks that are way worse then the rest.
The BIN Phase #2
Okayso you bought you 2 kits of high binned DDR4 because you know there will bejunk sticks mixed in. Now wat?
Now you bin, binand bin. Maybe you are so smart you didn’t even read this guide and you jammedyour expensive kit into your expensive board and now you are wondering why4000 MHz CL8 is not working for you. Stahp! Slow down! Step 2 is a longstep.
We are going to bin each stick one by one in slot B1 aka second physicalslot from the socket on the IO side.
You can use whatever settings you like to bin as long as you dont changesettings while binning.
Example: DDR4 binning by Splave
CL11 at3000 MHz using 4 GHz CPU speed and 4 GHz Cache speed at aDIMM voltage of 1.65v.
Find the lowest voltage it will take to pass SuperPi 32m consistantly. Now youhave found your best 4 sticks.
Don’t feel limited by my example. You can use 3200 MHz and C12 or anything youwould like (there are some suggested timings at the bottom of this article).
We aren’t done yet. Now we are going to try each of our 4 binned sticks in eachslot 1 at a time.
So start with A1 slot, find the lowest voltage for 32m. Then on the B1, D1, andthen C1. You will end up with a scientific list of why you are putting eachstick where they will fly the highest.
Pro tip: Slots in order from IO side to 24pin side goA1 B1 D1 C1. Dont get confused that they aren’t in alphabetical order on theboards left to right.
If you already know what you are doing and think this step is not necessary,gtfo and dont read my guide. Shamino labels his sticks for this reason nuffsaid?
Timings/Frequency Combinations.
So now that ourmemory is in its porperly proven correct slots, its time to max it out in quadchannel.
The best frequency to timing ratio is 3200 Cas 12 followed by 3100 Cas 11.
Here is astandard tight Hynix 3200 Cas 12 timing set using 1.65-1.72 V:
12-13-15-14-1N-10-260-4-6-3-9-4-24-3-9 4-6-6-6-7-7-2-1-3-3-1-1-3276749-49-49-49-6-8-6-8
Here is astandard tight Hynix 3100 Cas 11 timing set using 1.65-1.72 V:
11-13-15-14-1N-10-260-4-6-3-9-4-24-3-9 4-6-6-6-7-7-2-1-3-3-1-1-3276747-47-47-47-6-8-6-8
An importantthing to know is that memory training can be difficult with such tight timings.
So what we can do is keep it loose in the bios and for the training thentighten it down once we get into the OS using e.g. the AsRock TimmingConfigurator.
Keep in mind that tCL and tWCL will need to be set in the bios correctly as RTLand IOL’s cannot be changed in OS.
The key is totake the time to learn this over a week or two. It will make you a more wellrounded overclocker and will help almost every benchmark you run from hereon out! Don’t get frustrated by BD and BF bios codes, keep pushing and don’tgive up.
Questions orsuggetions? Let me know in the comments.
Splave – Overclocking.Guide
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