[SOLVED] Ryzen 3900xt and Viper 4400mhz (need help)

93boba

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Nov 24, 2015
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Hello!

Until recently I was able to run my memory on 4200mhz with the XMP profile. After updating bios and drives I am no longer able to.
My memory is running at 2300mhz which is pretty low.

I got informed that 4200mhz is overkill and that the optimal RAM frequency for Ryzen 3900XT should be 3600mhz.
My XMP profiles are only 4400 and 4200.

How can I manually set the RAM freq to 3600mhz?

I'd appreciate it if any expert is willing to tell me how to underclock Viper Steel 4400mhz to 3600mhz.



Processor AMD Ryzen 9 3900XT 12-Core Processor 3.80 GHz
Installed RAM 16.0 GB (Viper 4400mhz) (2x8GB/2A-2B)
System type 64-bit operating system, x64-based processor
Mobo Aours Master x570
Graphics 2080 OC
PSU Cooler Master 750w Gold (or platinum)

Edition Windows 11 Pro
Version 21H2
Installed on ‎30-‎Jun-‎21
OS build 22000.258
Experience Windows Feature Experience Pack 1000.22000.258.0


Benchmark (Before drivers/bios update):
https://www.userbenchmark.com/UserRun/36260233

Benchmark from today(unstable, rebooting system):
https://www.userbenchmark.com/UserRun/47265434
 
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93boba

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Okay here are the final results:

1# 3466Mhz/ 15 15 15 36 / 1.2V (Stable)
2# XMP 4266Mhz/ + High-Frequency Support Level 2/ 1.35V (Stable)
3# XMP 4400Mhz/ + High-Frequency Support Level 2 / 1.45V (Stable)
4400mhz UBM

4# 3600Mhz/1800FCLK/ 15-15-15-26 /1.35V (Stable)
3600Mhz UBM

5# 3800Mhz/1900FCLK/ 15-15-15-26 /1.37V (Stable)
3800Mhz UBM
 
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Bob.B

Respectable
Hello!

Until recently I was able to run my memory on 4200mhz with the XMP profile. After updating bios and drives I am no longer able to.
My memory is running at 2300mhz which is pretty low.

I got informed that 4200mhz is overkill and that the optimal RAM frequency for Ryzen 3900XT should be 3600mhz.
My XMP profiles are only 4400 and 4200.

How can I manually set the RAM freq to 3600mhz?

I'd appreciate it if any expert is willing to share his knowledge.



Processor AMD Ryzen 9 3900XT 12-Core Processor 3.80 GHz
Installed RAM 16.0 GB (Viper 4400mhz) (2x8GB/2A-2B)
System type 64-bit operating system, x64-based processor
Mobo Aours Master x570
Graphics 2080 OC
PSU Cooler Master 750w Gold (or platinum)

Edition Windows 11 Pro
Version 21H2
Installed on ‎30-‎Jun-‎21
OS build 22000.258
Experience Windows Feature Experience Pack 1000.22000.258.0


Benchmark (Before drivers/bios update):
https://www.userbenchmark.com/UserRun/36260233

Benchmark from today(unstable, rebooting system):
https://www.userbenchmark.com/UserRun/47265434
Both UBM runs show the ram is running at 4400.
Where are you seeing 2300?
 

mamasan2000

Distinguished
Perhaps 16-16-16 @ 1.45 volts. Generally XMP sets very loose tFAW etc, if it sets them at all. tRRDS, tRRDL and tFAW are all one package. 4-4-16 works for most. If it doesn't try 4-6-16.
But tightening secondaries...how many weeks do you want to spend? If you just set primaries, you could be done in a day, stability testing and all.
And if it is B-die, it is quite sensitive to temps, higher than 45 C. So it might be stable in a stability test but then you go and launch a game and that additional heat from GPU wafts over the RAM and drives up temp...RAM can get unstable. Particularly if you set an agressive tRFC.
 

93boba

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Nov 24, 2015
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Perhaps 16-16-16 @ 1.45 volts. Generally XMP sets very loose tFAW etc, if it sets them at all. tRRDS, tRRDL and tFAW are all one package. 4-4-16 works for most. If it doesn't try 4-6-16.
But tightening secondaries...how many weeks do you want to spend? If you just set primaries, you could be done in a day, stability testing and all.
And if it is B-die, it is quite sensitive to temps, higher than 45 C. So it might be stable in a stability test but then you go and launch a game and that additional heat from GPU wafts over the RAM and drives up temp...RAM can get unstable. Particularly if you set an agressive tRFC.
XMP for 4400mhz sets 1.45 volts and for 4200mhz sets 1.35.
Isn't 1.45 bit much for 3600mhz?

I can do it in a day or a week. Whatever it takes to do it properly!
Thanks
 

mamasan2000

Distinguished
XMP for 4400mhz sets 1.45 volts and for 4200mhz sets 1.35.
Isn't 1.45 bit much for 3600mhz?

I can do it in a day or a week. Whatever it takes to do it properly!
Thanks
RAM timings scale with voltage. The more voltage, the lower timings you can run. And B-die is the king at this. It is why it's the best you can get. Even at base 1.35 volts it has very tight timings compared to any other ICs.
I am guessing the 4200 Mhz XMP sets looser timings.

I have Micron Rev E and I have 2 profiles for it, manually overclocked.
  1. 3600 Mhz, 16-20-16 @ 1.47v GDM off 1T
  2. 3800 mhz 16-21-16 @ 1.,55v GDM on 1T
Because of the 2nd using 1.55 volts, I have a 120mm fan over the RAM. You shouldn't go past 1.50v without adding active cooling (=fans). For most chips. Samsung C-die, you shouldn't go past 1.35v no matter what.
Both of the profiles are using slightly different secondaries and other bits and pieces. 3600 Mhz has tighter secondaries as well. But, for added complexity, I had to play with ProcODT and DrvStrs at the same time as I was juggling with a timing at a time, just to get it stable. So that is juggling with 6 variables at the same time. That takes a lot of time. And it is hard to know which of those 6 variables causes the errors. Is it even 1 of them or a combination?
The 3800 Mhz profile was easy in comparison. For ProcODT and DrvStrs, I could just put them on Auto and it worked.
Here is a picture of timings so you get something visual: View: https://imgur.com/a/y1wqRFR

With B-die, you can generally run the SCLs at 2. tRFC between 120 and 180 ns. tRRDS/L and tFAW don't go any lower than 4-4-16.
As you can tell, Micron RAM needs a high tRCDRD. With B-die you can either keep it the same as tCL or 1 higher.

If you are serious about RAM OC, here is a great resource: https://github.com/integralfx/MemTestHelper/blob/oc-guide/DDR4 OC Guide.md
I use TM5 + Anta777 for all my stability testing. When I pass all 3 runs of it, I start using my PC as normal and if I crash, I attribute that to the RAM OC. You can usually tell by the BSODs etc. You will probably see a lot of them, OCing RAM. As soon as you get 1 error in TM5, something is wrong. You can quit the program and go back to changing the timing/resistance. Abd only change 1 timing/resistance at a time when you tune your RAM.
Oh yeah, and be prepared to 'Reset CMOS' 30-50 times per day so figure out the fastest way to do that. I have my cases Reset button hooked up to the 2 pins for CMOS Reset on mobo (thanks Buildzoid). I just need to hold down Reset button for 3 secs while PC is powered down and I can just get back to work. Use profiles! And save constantly! For added safety/convenience, use 2-3 profiles while dialing in stuff. 1 'known good', 1 'experimental' for example.
If you can't pass POST, either the timing is too tight or you are not applying enough voltage. If you are at 1.55v, it's the timing. Going over 1.55v is not recommended for daily usage.

Just be aware, you can corrupt your Windows install. Others use 1 install for RAM OC ONLY and another for daily usage. I am lazy and only use 1. If it gets corrupt, I will just reinstall.
 
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93boba

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RAM timings scale with voltage. The more voltage, the lower timings you can run. And B-die is the king at this. It is why it's the best you can get. Even at base 1.35 volts it has very tight timings compared to any other ICs.
I am guessing the 4200 Mhz XMP sets looser timings.

I have Micron Rev E and I have 2 profiles for it, manually overclocked.
  1. 3600 Mhz, 16-20-16 @ 1.47v GDM off 1T
  2. 3800 mhz 16-21-16 @ 1.,55v GDM on 1T
Can I try and copy yours 3600mhz? Should I give it a go?
 

mamasan2000

Distinguished
Can I try and copy yours 3600mhz? Should I give it a go?
There isn't much point (copying primaries). Yours will most likely be lower/tighter. Different ICs have different characteristics. But secondaries should be almost universal. There is variation there too but if you are within -2 to +2 on every secondary timing, it should work. This is where you will spend most of your time changing and testing for stability. Like 99% of your time.
To start with, I would set DRAM voltage to 1.45 or 1.50v, speed 3600 Mhz and start testing primaries one at a time, see how low they can go. If it posts, it might be stable. But you wont know until you boot to Windows. That is the first real test. Second test is the stability test. I got an error in Test 13 but that test is like 20-30 mins into the testing. So I opened the config file with Notepad and put 13 as the first test it runs and saved it under new name (remember to load that config in TM5). This way I save lots of time. Doing the full 3 runs...I do that once. Basically when I don't get any errors for 1 hour. Since I have 32 gigs, the full test takes 3 hours. If you have 16 gigs, it will take half that time.

Generally TM5 will spit out errors pretty fast, within 10 minutes, if you have unstable settings.

In terms of timings, I did search for my RAMs part number + 'overclock' added to the end of the search terms. Found a thread on overclock.co.uk or something. Looked at the Zentimings screenshot, read his comments about the RAM. Tried to replicate. It took me a good while. This is what he got it down to in 2 days, I think it was: View: https://imgur.com/a/0xta7Hh

tRCDWR at 8. I could use that as well but I don't see any performance gain. So I stuck with 16. I wonder if 8 even does anything or the mobo just reverts it to 16 without changing it in BIOS. I mean, you can set tFAW under 16. It just wont do anything. Because tRRD wont go under 4 and FAW is number of cycles after 4 Activate commands. So tRRDS * 4. That is 16. S and L = Short and Long. Long is used when data is in the same bankgroup. It needs a longer cooldown sometimes. Different bankgroup = Short.

View: https://www.reddit.com/r/overclocking/comments/ahs5a2/demystifying_memory_overclocking_on_ryzen_oc/


I spent considerably more time tuning my RAM, probably a month. There is slight variation, even though it is the same ICs.
So search for what others are running on the same RAM sticks. Find a couple screenshots of timings. And save them as a reference.
 
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93boba

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I spent considerably more time tuning my RAM, probably a month. There is slight variation, even though it is the same ICs.
So search for what others are running on the same RAM sticks. Find a couple screenshots of timings. And save them as a reference.
I tried your settings and I was even able to do a benchmark. However, after 20min the system got rebooted by itself.
GDM OFF / 1T

UserBenchmark
 

mamasan2000

Distinguished
I tried your settings and I was even able to do a benchmark. However, after 20min the system got rebooted by itself.
GDM OFF / 1T

UserBenchmark
I am not surprised. GDM off is the hardest overclock to tune and stabilise. You should start with GDM on, 1T or 2T. Then if you want to take it further, GDM off 2T and lastly GDM off 1T.
GDM off 1T should be the lowest latency off them all. It wasn't a huge difference for me. I did it mostly for the exercise, for the fun of it and for the challenge.
Did you stability test the primaries, one at a time? tCWL looks a bit low. That timing could work, doesn't have to be the culprit. But in general tCWL is tCL -2. In general. -3 or -4 can also work.
If you want to benchmark the performance, find a quick test. Aida64 is one, Cache and Mem benchmark. Linpack Extreme is 20 secs per testcycle but the first one can't be trusted so I would recommend at least 2 cycles (launch it, press 1,2,2, Enter, Enter). So that is 40 secs. Same with Ycruncher PI 1b, takes around 40 secs (included in Benchmate). Why short ones? So you can stability test sooner with TM5. There is no point on benchmarking for 20-30 minutes, that is wasted time. You should run long benchmarks exactly twice. Before and After. Stock settings vs OC.

In my case, GDM off 1T was really hard because I had to tune ProcODT, DrvStrs and timings, at the same time. It helps immensely if you have already done GDM on 1T stable OC at the same frequency. This way you know roughly what timings should work. You might even have to loosen some. ProcODT + DrvStrs, that is 5 variables. Plus what else other timings might be too tight. It isn't easy to test 6+ variables at the same time. You should start slightly looser to make it easier on yourself. Once the loose timings don't cause errors (=ProcODT and DrvStr are set up correctly, or very close to), then check if you can tighten timings further.

And you shouldn't need vCore SOC at 1.2 volts. It can cause instability at these clocks. Set it to 1.1-1.125v. Once you reach 4000-4200 Mhz, you might need 1.15v.
But start with tCL, everything else on Auto in the timings. Go as low as you can, til it no longer boots. Say that is tCL 14. Ok, so it wont do 14. Try 15. That boots? Boot to Windows, see if you can get to Windows without a BSOD within minutes. Run a stability test for 10-20 minutes. Then do the other primaries, same procedure. Bring them so low, your PC wont even pass POST, one at a time.

A tip on tRAS and tRC. You can calculate the lowest safe timings. These will work every time. They have for me, without exception.
tRAS = tCL + tRCDRD+2. From your screenshot that would be 16+16 +2 = 34.
tRC = tRP +tRAS. 16+36 = 52.

Oh yeah, I forgot. TURN FAST BOOT OFF! Memory wont train with it on. There is not only the settings you have access to, there is also hidden timings. That the mobo sets at boot-time. If Fast boot is off. So you could be tripping and falling there.
 
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93boba

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I am not surprised. GDM off is the hardest overclock to tune and stabilise. You should start with GDM on, 1T or 2T. Then if you want to take it further, GDM off 2T and lastly GDM off 1T.
I made these additional changes:
  1. GDM ON 1T
  2. tCWL 14
  3. vCore SOC to 1.125v
  4. tRAS 34
  5. tRC 52
My bios got corrupted and couldn't boot. Fortunately, I have the backup bios so I was able to recover and fix the things.
vCore SOC 1.2v is x570master default. Changing its value was the thing that corrupted my bios?
Any recommendation? How do I avoid BIOS corruption? What values to adjust?
 

mamasan2000

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I made these additional changes:
  1. GDM ON 1T
  2. tCWL 14
  3. vCore SOC to 1.125v
  4. tRAS 34
  5. tRC 52
My bios got corrupted and couldn't boot. Fortunately, I have the backup bios so I was able to recover and fix the things.
vCore SOC 1.2v is x570master default. Changing its value was the thing that corrupted my bios?
Any recommendation? How do I avoid BIOS corruption? What values to adjust?
I can't see how that corrupted anything. Were you flashing BIOS at the same time as you booted?
What you might have come up against is, BIOS not POSTing. Normal if you OC. What you should do is a CMOS Reset. If you OC for a day, expect it to happen 30-50 times that day.
POST = Power On Self Test. Bios does it every boot.

You changed 5 things at once. How will you know what caused what? You wont. Take it slow, start easy. Set primaries to something easy. Like 18-18-18-38-56. Everything else Auto. Then take 1 setting, focus on just that, and start bringing it down.
Motherboard defaults sometimes suck. Just look at MSI Gaming Edge X570. I've never seen worse in 20 years of PCs. 1.2v SOC is not required for 3600 Mhz, I don't care what your mobo says. Someone tested this. It is like 1.08v or something. But you don't want to sit at the absolute minimum either.

Default voltages...my mobo sets VDDGs, both of them, to 1.05v. That is fine. Not required but it's fine. MSI Gaming Edge sets them to 1.10 volts. Not fine. VDDG IOD over 1.08v causes instability for most folks, especially when overclocking RAM and/or Fclock.
For me too. The VDDG CCD, I haven't seen any benefits of it going past 1.0 volts but I also have a 1 CCD CPU, the 5600X. It might be different for the CPUs with 2 CCDs. I can't test that.
CLDO_VDDP should be below 1 volts. Somewhere around 800-960 millivolts. That is usually set by mobo within those values.
My brother has the MSI Gaming Edge. Not only does the VRM overheat when running a stock 3900X. Stock! The XMP timings it sets is through the roof. I'm mad about it. How is that junk even legal to sell? Rant over.

Here is a database of peoples latencies, voltages, Fclocks etc. Sorted by lowest latency https://docs.google.com/spreadsheets/d/1dsu9K1Nt_7apHBdiy0MWVPcYjf6nOlr9CtkkfN78tSo/htmlview?pru=AAABfObdT8w*mLDryGKc9iAN-oJiW2lIoA
You could use it as a reference. See if you can find your motherboard on there and compare what they are running. Now, when it comes to Fclock, it is heavily down to silicon lottery. Only around 10% can run Fclock over 1900 Mhz, on 5000-series CPUs. I can't. I've tried everything. For weeks. But still, it should be somewhat useful, for the voltages, resistances, performance you should reach. ProcODT, RTTs and DrvStrs are resistances. Has to do with RAM signal integrity. In other words, vital for stability.
 
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