Updated first posts with B-die info and experiences.
***
Since this guide was originally posted before Samsung B-die made an entrance in them market,I decided to add my experiences with it later on the path.
B-die a.k.a K4A8G085WB started manufacturing middle of 2015 with the first IC carrying week 524 code on Samsung OEM and 528 on 3-rd party vendors(according to my own research) .
It shares a lot with previous E-die in voltage/mhz/tcl scaling while also allowing ridiculous low TRCD-TRP limits which simply makes it the best choice in overclockers arsenal .
At the moment 70% or more of the market B-die seems to be manufactured at the same factory with the same 10-layer pcb as you can see in following picture , Teamgroup , Zadak511 and G.skill sharing same PCB together with Galax and possible others too.
As good as it is for benching ,this Particular IC has it’s flaws also .Those seem to be :
-Voltage tolerance
-copy-wazza issue
Regarding voltage tolerance B-die seems to be less permissive than E-die,with a lot of sticks getting issues at 1.95V and over .
Considering B-die voltage scaling is like 0.1V per each 133 mhz at TCL12(e.g DDR4-3733 12 12 12 required 1.67,DDR4-3866 requires 1.77,DDR4-4000 requires 1.87 on same stick) it is clear that the goal is to find sticks that are decently in voltage requirement at DDR4-4000 (under 1.95V) but tolerating 2.05 .Please note that voltage tolerance does not improve with cold or different cpu or motherboard.
Copy-wazza issue was discovered and currently seems to be the flaw of many sticks . The flaw it’s simple, module will run every benchmark at a given frequency and timings except S-pi 32M with copy-wazza tweak which required 200-300 mhz less for benchmarking. Based again on my own research it seems that the flaw is related to B-die production weeks and my testing showed that:
-sticks 534-540 including 540 will pass most of the times wazza ;
-543 has a 50% chance of passing wazza;
-545 549 552 will fail most of the times ;
-601-616 has a decent chance of passing wazza;
-619 will pass most of the times wazza (80%+ in my testing)
4-dimm motherboards will have a hard time running B-die over 3866 and if your goal is to reach DDR4-4000 12 12 12 on these motherboards ,serious binning of the motherboard is required.
Therefore almost all of my testing was performed on Maximus VIII Impact which can handle way better the 8GB sticks.
Similar to E-die , Samsung B-die allows very tight tertiary and secondary timings,compared to previous generation trfc can actually go very low like 180 at 4000+ without however any significant performance improvements in SuperPi. A value of 240 should be good match for stability and performance as some sticks can have problems regarding 200 or lower at 4000+.
The following combo should not limit overclocking or performance :
Please note in rare cases some sticks may not like Write Recovery time and TRTP,therefore don’t forget to try relaxing this as last resort.
An important note also is that tertiary TWRWR_dr and _dd actually benefit from values like 4-4 or 5-5 on Asus Maximus motherboards compared to rest of the IC’s tested.
Maximus VIII Impact can handle very tight RTL at 4000+,typical values are 49-50-6-6,50-50-7-6,50-51-7-7,51-51-8-7.
These advanced SLOPES settings may give you a little boost in improving stability and MHZ:
For my particular IMC/Motherboard combination the outcome at 4133 12-11-11 timings was the following:
-ALL AUTO loop 14-15 would crash;
-ALL SET 15-1 Initial round failed;
-ALL FALLING SLOPES 15-1 ,rest auto would fail to load windows;
-ALL RISING SLOPES 15-1 ,rest auto would pass loop after loop with wazza.
Also note that increasing slopes value will give VCCIO a better scaling.
DEBUGGING B-DIE
So you got yourself one or more B-die sets for benching and you want to check the potential on your Maximus VIII Impact. You might want to check on the following issues.
1. Eternal boot of the spotless B-die
Some sticks exhibit this issue even at DDR4-3733 12-12-12 ,they will need over 1 minute to start OS loading.However most of the sticks would manifest this when going over 4000 12-11-11 . This behavious will be manifested on other brands of motherboard so it is not specific to Maximus VIII series.
You will first notice a long wait at 79 code then another long wait at b4 ,culminating with another long wait at 99 then finally pushing into a weird error code regarding Mei before finally entering OS.
Also this is related to not being able to shutdown or restart from OS being stuck at 04 ore 05 code .
As weird as this may sound, a stick that had this behavior at 3733 12-12-12 could pass DDR4-4080 12-11-11 with copy-wazza so on current platforms there is no connection between this behavior and benching potential.
Cooling the memory to -50 or lower got me rid of this behavior but overclocking potential did not get better sadly.
2. Voltage tolerance behavior
4F is the debug code on B-die for expressing that you passed the voltage tolerance limit on your sticks.
For example on most of the sticks I could bench relative stable 0.03-0.04 under this limit . When you reach the “Danger Zone†the stick will let you know it is not confortable by either getting weird blue-screens or by receiving “NOT CONVERGENT IN SQRT†error in SuperPI 32M.
3. Different behaviours under stress
- NOT CONVERGENT IN SQRT while running 32M,either problem with voltage tolerance or TRCD too tight
-exit benchmark while running 32M, either too tight RTL or too low VCCIO, 1.35V and -100 will definatly maxxx-out your IMC potential.
-errors in DJIKSTRA test of Geekbench , try lower-higher voltage than 32M .
-XTU errors . In my case XTU required higher TRFC for complete stability than 32M,however XTU also benefits lower trfc to 200-220 so the only way of having complete stability for bugging the ultimate score was cooling mems to 0-10 degrees.
***
