Encountered this a lot,usually: 3E means too low Write Recovery / read to precharge time 78 means too tight TRCD/TRP 41 Means you went too tight on tertiary or you pushed too much voltage on Hynix MFR 55 well this means a lot,from not enough voltage for give settings,too tight TRFC ,improper tertiary.
ISSUE # 3
General behavior of various IC
Hynix MFR is the classic of X99 and actually the WORST performer on AIR . It has many problems on AIR,meaning hard to get high frequency and tight CAS . Worst voltage tolerant IC , creates many problems like you can pass DDR4-3200 12-15-15 at 1.58 V, 1.54V gives can?t train 55 and 1.62V gives you 41 because the voltage is too high . The best sticks to look for are the ones that support higher voltages at higher speeds , good sticks can bench DDR4-3200 12-15-15 under 1.6V and with good voltage tolerance they might get you to DDR4-3333 12 +
Hynix AFR is the improved die from Hynix . Fixes many of MFR flaws and it?s a huge improvement . Can tolerate high voltage at high speeds and run great on X99 and Z170 . They will be available very soon on Kingston HyperX memory and other vendors will implement too for sure.
Typical benching scenarios are DDR4-3600 12-17-17 at 1.65 DDR4-3733 12-18-18 at 1.75 DDR4-3866 13-18-18 @1.85 DDR4-4000 firstname.lastname@example.org
Of course voltage might vary and be aware they are harder to clock compared to Samsung,my few sticks can?t manage over DDR4-3733 on any board but Impact ( 1 dimm per channel board)
Samsung D-Die K4A4G085WD
First die from Samsung has good voltage tolerance and can be found on a lots of modules from different vendors from Gskill 3000,3200 Ripjaws,early 3466 and 3600 Ripjaws-V and Trident-z to Corsair lineup and so on . Can go up to 2-2.1V on air and scaling is linear . Typical benching scenarios are at DDR4-3733 15-19-19 for worser kits with 1.8-1.9V to better sticks doing even 13-18-18 .
Samsung E-DIE K4A4G085WE
Second revision from Samsung gained huge improvements . Voltage tolerance is great,taking up to 2.1V at 4200+ speeds ,trcd limits have gone lower and overall it looks like a very solid IC. Typical benching scenarios are: DDR4-3600 11-17-17 at 1.9V and under DDR4-3866 11-19-19 at 2.05V and under DDR4 -4000 12-20-20 at 2V and under
So far to be found on G.skill Trident-Z and Ripjaws-V kits on week 38 and higher , Teamgroup inferior bin of 3866 18-22-22 and newly Corsair 4000c19 . The best modules to aim for are low TRCD ones, generally aim for DDR4-3600 TRCD/TRP 17 and DDR4-4000 TRCD/TRP 19 . They are the easiest to clock modules and also can go lower in tertiary/secondary ,TRFC of 280 at 4200 speed should not be a problem for good sticks.
ISSUE # 4
2 DIMM vs 4 DIMM
4 DIMM is ALWAYS faster than 2 DIMM at similar clocks/timings . Early results in XTU benchmark showed that , however this puts more stress on IMC and result in looser timings sometimes. The only timing to be adjusted is TWRWR_DD which has to be 8 otherwise platform will not start. Keeping identical secondary/tert timings at same clock speed on 4 ghz 32M test this is about 1 second faster at DDR4-3466 C12 which is quite a difference in 32M world.
Please NOTE that AUTO RTL/IOL on 4 DIMM scanarios will give you very loose IOL,this is because Maximus boards will automatically set IOL_latency offset 15 instead of default 21 when 2 dimms are used. Easy way to fix this is to manually set 21 for better performance.
ISSUE # 5
BAD RTL Training
Sometimes the memory training is missed and you can see big difference in RTL/IO,for example instead of 50/51/7/6 you will have 58/51/14/6 and similar.This WILL hurt the performance a lot in 32M and XTU too,It is always best when finding proper RTL/IOL combo to manually lock them by overriding AUTO so you will have same values every time.
Example : Samsung D 3733 C14 normal RTL vs fail RTL :
The TWRWR_DR and TWRWR_DR timings .
Being advocated to go as low as it can this is actually a big lie as tested on all ic available I had found that going lower actually hurts and optimum value for high and medium speeds is actually 8 . Tested on MFR,Samsung E-die and Kingston AFR,4 4 is worser than 8 8 period . AFR DDR4-3866 13-18-18 TWRWR_DR TWRWR_DD 8 8
0.300 Sec Worse Hynix MFR DDR4-3200 12-15-15 TWRWR_DR TWRWR_DD 9 9 same as 8 8 result
TWRWR_DR TWRWR_DD 4 4
1 SECOND Difference at slower times !
TWRRD_DR and TWRRD_DD Actually encountered this issue when I left this timing on AUTO and went from DDR4 3466 C12 to C11 and got a worser score !. After a few tries I found that AUTO gave me 6 6 and after lowering this to 5-5 performance gain was normal . It actually can go lower to 4 4 and 3 3 but performance was similar to 5-5 on Hynix AFR and worser on Samsung E-die and stability was a little bit worse so I would recommend 5-5 in all cases period.
General rule is that they go tighter with CAS going lower and they are linked with Write to Read Delay L and S . Write to Read Delay L and S can go lower than 6 even to 1 but show no performance increase whatsoever,except when lowering them by TWRRD_SG and TWRRD_DG.
For example the settings pictured above resulted in showing 7 7 for write to read delay L and S although they were set at 6 in UEFI .
Lowering TWRRD_DG from 22 to 18 resulted in showing 7 and 3 :
The performance boost is little but might matter on
Since we are talking about Write to Read Delay(not L and S), this timing can go as low as 1 and see little performance boost
TRDRD_dr and TRDRD_dd
This is actually interesting because of conflicting results.While testing IC from Hynix and Samsung I noticed that Hynix prefers this two timings at 0 0 gaining almost half a second boost while Samsung prefers the other way around having the best results at 5 6 .Even complementary values like 4-5 5-5 6-7 gave worser results so my findings are that if you own a Samsung based memory this have to be set at 5-6 while Hynix likes them at 0-0.