DDR Training ??

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ggilmour53

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I have MSI Unify z490 ATX
I am trying to find out how to use DDR Training mode,
I have not found anything on how best to use Training module with in the Bios
 
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With your input I am quite happy with the results.
This will keep me going until DDR5 starts to arrive, do you have any insight as to what the first batches of DDR5 will bring??
 
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You mean you don't see the list of BIOS versions? Maybe their servers are acting up again. Although it works for me at the moment.
 
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I noticed on boot after a long gap ( me sleeping ) that the RTLs or IOLs were out of sync a little but after a restart they were OK, so I thought I would try lowering tRFC to 620 with this in mind so it did work , exampes follow first img the cold boot second img the restart Is this normal behavior ??
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Is "Memory Fast Boot" disabled or enabled or Auto? Auto should be enabled. I like to set it to disabled, then the RAM trains on every boot. This way, at least for the RTLs/IOLs, it can determine the best value each boot. When you notice that they're wonky sometimes (e.g. 74/70 + 15/9), maybe some other setting is also a bit too tight for comfort. It doesn't always have to be tRFC. But if it is tRFC, you can set it another 10 higher, doesn't make a big difference.
 
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Disabled is ok. I use that too. Auto/Enabled boots faster, but with manually optimized RAM timings, it's more important that it always passes training reliably. Since it trains on every boot, you would notice immediately if there's a failure, because it would show the "Overclock has failed, press F1/F2" error message during POST. Which could happen on a very hot day, with timings that would juuuust about work on a cooler day, for example.

At this point, my RAM is so stable that i could probably set it back to Auto and enjoy a couple seconds less training time each boot. Once your RAM always trains rock stable, you can set it back to Auto.
 
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I was wondering why we are getting DDR5 ram for next gen motherboards when I have DDR6 on my GPU which is running at a stock 14000mhz. Is it the price?
 
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On the graphics card it isn't DDR6, it's GDDR6. The development is not parallel with DDR, meaning, GDDR6 is still somewhat comparable to DDR4, and is not two steps ahead. As for the frequencies: Since GDDR is soldered onto the PCB, and is right next to the GPU, it's much easier to optimize for high freqencies than normal RAM modules that have to be plugged into sockets.
 
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citay said:
It all depends on your modules, the chip density on the modules, and the frequency the RAM is running at. The higher the density of the chips on the module, the longer the refresh has to be, and therefore the higher tRFC has to be. Density means for example, a 16 GB module using 8 chips has double the density of an 8GB module using 8 chips. Then there are known values to which certain types of chips can go down to, again, depending on the chip in combination with the frequency it's running at. If you run at DDR4-4266, your tRFC has to be higher than at DDR4-3600, to arrive at the same amount of time in nanoseconds.

View attachment 141263

However, tREFI (the interval between refreshes) is always officially deemed to stay the same 7.8 μs (microseconds, from mikros = small in Greek). There is no such dependency on density etc., but instead they said, this is a proper value for DDR4 RAM that will ensure that there's never a problem, no matter the module. This, of course, is thrown overboard with RAM OC. You see most OC guides recommend to max it out at 65K. But most overclockers who write these guides only tend to test for stability. As i said, data retention is much harder to test, the bit fade test in Memtest86 attempts to do it, but i don't see much RAM failing on that part of testing. Maybe it has to be tested in a worst-case scenario like i mentioned before, because as the modules get hot, the official specs call for double the refresh cycles (every 3.9 μs).

I try to stay more on the safe side and go to tREFI 32K with my Samsung B-Die. There is really no scale for it. If you want to be safer, stay at 32K, if you want to challenge something that's hard to test, go to 65K at your own risk...

Note that in the above table, tRFC is in nanoseconds. That is not the value you enter in the BIOS, that one is in clock cycles. To calculate the tRFC value, there is this table:

View attachment 141264

350 ns at DDR4-3600 means a tRFC value of 630 clock cycles. Depending on the chips/ICs used on the module, you can go a bit lower, a bit more lower, or way lower in the case of Samsung B-Die. B-Die should be good for 160-180 ns. This is one of the main strengths of it. For your DDR4-4266, if it were B-Die, you would be able to set tRFC as low as 340-380 clock cycles. But with other chips, this is not possible at all. With Hynix CJR, you're looking more at 280 ns as the lowest time, which means, you could try tRFC 600 at your frequency, looking at the above table.
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what would be the ideal values for various frequencies for 2X16 gb bdie ram ? like the xmp sets trfc , trfc 2 and 4 on my asus board
i wanna know what the best trfc for 3200 , 4133 , 4266 ?
also can you eloborate on what is trfc 2 and 4 ?
 
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At DDR4-3200, with 2x 16 GB B-Die, i'd probably set tRFC 300. At -3600, set 320, at -4133, set 380, at -4266, set 400. These are values that should not cause you any problems. tRFC 2 and 4 are used when the RAM reaches very hot temperatures (>85°C), so they would never come into effect anyway.
 
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