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Well there you have it. 75C after 5mins of stress. That's hot! I'm not surprised that some of the OC can only last for like 30mins under full load. Its not the CPU that is causing issues, its the mobo.

I'd say, keep those VRMs below 70C under 24/7 stress test, and you should see a bit more wiggle room. Really cool them, and you may get more but it will tapper off quickly.

I think the key to RyZen will be to keep the entire system as cold as possible rather than just the CPU like it has been in the past. Again no first hand experience just yet.
Why do you think 75C is problem for those regulators? You provided the link which shows ATMINSIDE's response below, giving the temperature range for those MOSFETs as -55°C to 150°C. If they're rated for 150C how can 75C be a problem for them?

Those are MOSFET-Transistors manufactured by ON Semiconductor. Full part number NTMFS4C06B and NTMFS4C09B. Very standard fare for a good VRM's MOSFETs.
Operating temperature range of -55°C to 150°C. They're more than happy at 85°C.
 
Ryzen 1700, Asrock X370 Killer, Team Dark 3000mhz(if only), MSI 980T Gaming. Ram aspect is frustrating. But the multitasking aspect is quite nice. A bit of a change from my 6700k

VwvWppl - Imgur.jpg
 
Yeah the ram situation is still far from ideal but still do-able on some boards
 
Why do you think 75C is problem for those regulators? You provided the link which shows ATMINSIDE's response below, giving the temperature range for those MOSFETs as -55°C to 150°C. If they're rated for 150C how can 75C be a problem for them?

As the temperatures go up MOSFET's ratings will go down. This is a 4C10N like what is found in the powercolor red devil 480 and the XFX cheap 480's

http://www.onsemi.com/pub/Collateral/NTTFS4C10N-D.PDF

They go from 44A @25C to 33A @80C for continuous drain. Depending on the quality of MOSFET those ratings can plummet.
 
As the temperatures go up MOSFET's ratings will go down. This is a 4C10N like what is found in the powercolor red devil 480 and the XFX cheap 480's

http://www.onsemi.com/pub/Collateral/NTTFS4C10N-D.PDF

They go from 44A @25C to 33A @80C for continuous drain. Depending on the quality of MOSFET those ratings can plummet.

You got it CDawall and it's not linear. Their efficiency drops very fast with every degree they go up


At a guess I'd say single rank Hynix
 
I can borrow the IR camera again and try same on my X370 build which does have heatsinks over the VRM. I have dared to OC that system too so can compare stock vs. a mild OC to 3.6 or maybe a little more...
 
As the temperatures go up MOSFET's ratings will go down. This is a 4C10N like what is found in the powercolor red devil 480 and the XFX cheap 480's

http://www.onsemi.com/pub/Collateral/NTTFS4C10N-D.PDF

They go from 44A @25C to 33A @80C for continuous drain. Depending on the quality of MOSFET those ratings can plummet.

Not a big deal.

You're delivering (OC'd) a max of 200W @ 1.4V. That means approximately 140A.
On the ASUS Prime B350M-A there are TWELVE of the NTMFS4C06B as the final MOSFET in the equation.
This means they need to supply a max of 12A per MOSFET. They are rated for 52A at 80°C.
 
Above 100*C vrm is visible instability. I'm not sure where is the sensor but part of vrm have no heatsinks ( still additional fan is not helping ). It happens only during longer runs at 100% load ( like new Prime95 ) and above 1.4V ( more like ~1.44V ). No one said it's a motherboard designed for top OC and I guess that many other B350 boards have the same issues. It's just how ryzen is scalling under load and any higher voltage above stock ( up to 1.4V is still stock ). Difference in vrm temps between 1.35V and 1.45V is about 25*C under full load. During benchmarks, temps are usually not much above 70*C at 1.45V. During gaming will be the same.
I have the same OC results on ASUS X370-Pro as on Gigabyte AB350-Gaming 3. In both cases fully stable is 3.90-3.95GHz ~1.35V. B350 boards are not really designed for max OC. There are barely any OC options. I just don't think that average user will complain. It still can make 3.9GHz without any issues. It runs memory up to 3200 without any issues. I also have no problems with stability in OS. At 3.9GHz all temps should be way below max safe values.

If you are looking for max OC then something 10 phase or more will be required so there are maybe 4-5 boards like that. On the other hand difference between average B350 and the most expensive X370 is up to 100MHz on ambient cooling while X370 cost up to 2x more. All depends on what are you expecting.
Now if you want to get the best results then you need bclk adjustment which so far I've seen only in ASUS CHVI. Prime has it disabled and I guess that top MSI has it too but I just haven't seen this board.

Are you having visible instability at 3.9GHZ with ~1.44v core? According to Elmor at Asus, motherboards set with auto CPU core voltage should be able to handle Reading of 1.467-1.48V is fine, within error margin and AMD spec.
 
Not a big deal.

You're delivering (OC'd) a max of 200W @ 1.4V. That means approximately 140A.
On the ASUS Prime B350M-A there are TWELVE of the NTMFS4C06B as the final MOSFET in the equation.
This means they need to supply a max of 12A per MOSFET. They are rated for 52A at 80°C.

What is max case temp for those? I have had issues in the past where anything over 100C would cause instability regardless of amperage pulled. Not saying that is the case here more of a curiosity.

Also those ratings don't quite compare like that...
 
The point I am trying to make to you guys is that when temperature increases, the current capacity of each phase lowers. This can go south very quickly with each step up in current.

kw6BOL9.png

In fact its exponential. With every little step in temperature, the current will ~squarely decrease. And with each increase current, the temperature will ~squarely increase. So when you increase voltage, you increase what current capacity to the CPU. This increases temperature, thus decreasing current capacity in a faster means, and will continue to do so because Temperature is function of Time. In the case of DaveB is roughly ~30 mins before everything goes capute
 
The point I am trying to make to you guys is that when temperature increases, the current capacity of each phase lowers. This can go south very quickly with each step up in current.

kw6BOL9.png

In fact its exponential. With every little step in temperature, the current will ~squarely decrease. And with each increase current, the temperature will ~squarely increase. So when you increase voltage, you increase what current capacity to the CPU. This increases temperature, thus decreasing current capacity in a faster means, and will continue to do so because Temperature is function of Time. In the case of DaveB is roughly ~30 mins before everything goes capute

Don't the engineers have over-current protection for the VRM so it will throttle the CPU like AM3 budget board were doing? I don't see folks complaining about AM4 B350 budget motherboards throttling, so I don't see a problem. If there was a problem like you say, we would see a Vcore voltage drop, then a Crash.
 
Don't the engineers have over-current protection for the VRM so it will throttle the CPU like AM3 budget board were doing? I don't see folks complaining about AM4 B350 budget motherboards throttling, so I don't see a problem. If there was a problem like you say, we would see a Vcore voltage drop, then a Crash.

No you won't. The cpu clock will drop if it is setup correctly. Just like it did on every throw away am3 board.
 
No you won't. The cpu clock will drop if it is setup correctly. Just like it did on every throw away am3 board.

That is what my point was, the clock will throttle. However Dolk is technically saying the Vcore will drop first with the AM4 B350.:eek:
 
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