Ryzen 3900X (or 3950X) on X370.

TheSlySyl

Limp Gawd
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May 30, 2018
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You got 60% at stock, omfg? That means your board is goosing the chip by quite a bit
That was exactly my thinking and would also explain the 50C+ idle temps.

I know my board was never made or expected to have a 3900X and that there was a risk involved. So I'm honestly just shocked at the stability of all this.

I'll disable PBO tonight after it goes idle again. I don't expect the transcoding job to be done for a while.
 

GSDragoon

Limp Gawd
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Feb 24, 2004
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169
Yeah, temps can spike up very quickly and fluctuate a lot. It sounds like you have a lot of stuff in the background keeping things warm. Get a true idle system and only monitor the CPU temp. It will probably go down.
 

Azif

n00b
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Jul 24, 2020
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1
Any tips?
I have the same board gaming K4 and just got a 3800x so assume it should run...
 

sabrewolf732

Supreme [H]ardness
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Dec 6, 2004
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nice to see these 3900x's are so toasty. I just got mine set up with a raystorm pro, 420mm radiator, and d5 pump and I also idle in the high 40's to 50s. Prime 95 load goes up to 80c. I remounted block twice.
 

TheSlySyl

Limp Gawd
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May 30, 2018
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416
Any tips?
I have the same board gaming K4 and just got a 3800x so assume it should run...
Yeah, update the BIOS, I mentioned the exact revision that I used in a previous post, but the board booted with my 1700 all the way up to 5.50 (AGESA 1.0.0.3)
Once I got the new CPU installed and got to windows I updated the BIOS again.

After some memory tweaking everything was stable.

I then had to massively undervolt my processor to get temps in line, but that could be particular to my motherboard or situation.
 
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sirmonkey1985

[H]ard|DCer of the Month - July 2010
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Sep 13, 2008
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nice to see these 3900x's are so toasty. I just got mine set up with a raystorm pro, 420mm radiator, and d5 pump and I also idle in the high 40's to 50s. Prime 95 load goes up to 80c. I remounted block twice.
just the nature of the beast.. chiplets are too small to transfer heat efficiently to the IHS. that being said make sure you don't have high performance mode set in the windows power settings. should also make sure you have minimum cpu set to 5%. should drop your idle temps so that it drops below 1v at idle.

Yeah, update the BIOS, I mentioned the exact revision that I used in a previous post, but the board booted with my 1700 all the way up to 5.50 (AGESA )1.0.0.3
Once I got the new CPU installed and got to windows I updated the BIOS again.

After some memory tweaking everything was stable.

I then had to massively undervolt my processor to get temps in line, but that could be particular to my motherboard or situation.
just be careful with undervolting because zen 2 isn't like old processors were it'll just instantly black screen due to low voltage. the cpu will still attempt to run and lower clocks internally even though the reported clock speeds look normal so double check your performance with something like CB20 at stock and then undervolted. i think it was der8auer that did a video talking about it.
 

thesmokingman

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nice to see these 3900x's are so toasty. I just got mine set up with a raystorm pro, 420mm radiator, and d5 pump and I also idle in the high 40's to 50s. Prime 95 load goes up to 80c. I remounted block twice.
You are probably looking at the default cpu sensor. P95 will load up to 80c, that's a given its Prime. Now if you are loading Cinebench to 80c then yea you would have a problem. Regarding the cpu sensor, default reading on 99% monitoring apps shows not only cpu temp, but also all 24 individual cpu sensors, and temps for both CCD. That's why you see high temps because the cores are reacting to context switches, basically doing their job in ms.

My 3900x idles at 35c, doesn't spike up at all. That's because I'm not using the default cpu sensor, instead am using die average.
 

sabrewolf732

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You are probably looking at the default cpu sensor. P95 will load up to 80c, that's a given its Prime. Now if you are loading Cinebench to 80c then yea you would have a problem. Regarding the cpu sensor, default reading on 99% monitoring apps shows not only cpu temp, but also all 24 individual cpu sensors, and temps for both CCD. That's why you see high temps because the cores are reacting to context switches, basically doing their job in ms.

My 3900x idles at 35c, doesn't spike up at all. That's because I'm not using the default cpu sensor, instead am using die average.
What are you using for temp monitoring?

sirmonkey1985 seems like my idle voltage is constantly ~1.4-1.5v
 

thesmokingman

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TheSlySyl

Limp Gawd
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May 30, 2018
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just wondering why not just go for a b550 or an x470?
I already had an X370 board installed and I didn't want to spend the money or time to upgrade it to a B550 or X470. Now that I'm at at over a month with my 3900X on my X370 and before the last windows update, I was sitting at 18 days uptime. I think I made a good decision.
 

orijin

Weaksauce
Joined
Aug 22, 2010
Messages
71
I already had an X370 board installed and I didn't want to spend the money or time to upgrade it to a B550 or X470. Now that I'm at at over a month with my 3900X on my X370 and before the last windows update, I was sitting at 18 days uptime. I think I made a good decision.
True if money is a factor, might as well leave it as it is if its still working
 
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