Why Does Vcore Fluctuate More Than SVI2 TFN Voltage Readings?

[Dave1001]

I monitor both the SVI2 TFN and Vcore for my 5800x; both of which obviously fluctuate under load. the SVI2 TFN is typically within 1.2-1.4v, while the Vcore can be a bit more 'reactive', I guess? for example, I will often see the Vcore in the 1.2-1.3v range, while also dropping down into the 1.1v's, and even a solid 1v sometimes


why is this? is there a reason the Vcore drops a lot more compared to the SVI2 TFN (which as I understand, is the VDDCR voltage). under load it likes to specifically drop to occasionally to 1.184v before going back up. am I risking any kind of instability or facing a symptom of some problem with this behavior or is it a harmless drop in voltage caused by the way the motherboard/CPU handles itself?

I have no overclock; just Eco Mode 65w enabled

 

[slybunda]

VID is what cpu wants, SVI2 TFN is what cpu gets. voltage regulator and vdroop stuff causes the difference im guessing. be lucky iv seen vid as high as 1.544 and SVI2 TFN at 1.513 on my 5900x. had to manually set a negative voltage offset to keep vcore below 1.45v otherwise it will degrade.

 

[Dave1001]

VID is what cpu wants, SVI2 TFN is what cpu gets. voltage regulator and vdroop stuff causes the difference im guessing. be lucky iv seen vid as high as 1.544 and SVI2 TFN at 1.513 on my 5900x. had to manually set a negative voltage offset to keep vcore below 1.45v otherwise it will degrade.

I basically pay no attention to VID, when it comes to voltage I just look at SVI2 TFN and Vcore. if I see my Core VID a bit too high compared to what I normally see, I start poking around because usually that means one of the other voltages are high too, but otherwise I mostly ignore it

 

[slybunda]

with zen 3 if SVI2 TFN goes over 1.50v then it degrades instantly?

 

[buddywh]

with zen 3 if SVI2 TFN goes over 1.50v then it degrades instantly?

As with all semiconductors, it's perpetually degrading any time it's operating, with any voltage, a higher voltage degrading it faster. I don't imagine the degradation rate is linear, much more of a curve that's starting the turn northward above 1.5V. I've read where AMD has stated occasional boosts above 1.5V, maybe to 1.55V, are expected with Zen2 and 3 CPU's but usually only after first starting up or when the CPU is real cool.

I've also noted how much more active the VCore voltage is. That's in the motherboard super I/O sensor section so I think it's the output of the VRM and before VDroop in some motherboards depending on where the sense line is connected. If the SVI2 voltage reading is from the CPU itself it's after VDroop. But more, VCore on my motherboard frequently falls to just above 1.0V and stays around there with only occasional spikes above 1.45V even when the SVI2 voltage is running pretty steady around and above 1.4V. That's never made much sense to me.

 

[slybunda]

I suspect lifespan of these ryzen cpus is expected to be not much more than the warranty period, iv still got 1st gen intel core i7 systems in operation today going strong with no signs of degradation after 10 years of operation.
Guess thats the price in lifespan amd have to pay to compete with intel?

 

[buddywh]

I suspect lifespan of these ryzen cpus is expected to be not much more than the warranty period, iv still got 1st gen intel core i7 systems in operation today going strong with no signs of degradation after 10 years of operation.
Guess thats the price in lifespan amd have to pay to compete with intel?

I suspect you're very much wrong.

 

[slybunda]

I suspect you're very much wrong.

please enlighten me, 1.55v going into these 7nm cpus is too much for long term reliability. its already been reported that zen2 and zen3 have very high failure rates and it seems to be linked to these high voltages the cpus run. live fast die young motto for amd.

 

[buddywh]

please enlighten me, 1.55v going into these 7nm cpus is too much for long term reliability. its already been reported that zen2 and zen3 have very high failure rates and it seems to be linked to these high voltages the cpus run. live fast die young motto for amd.

First of all, you said "instantly" which is not long term. Out of my own curiosity I frequently monitor with HWINfo and I've never seen an instance where my 5800X, nor my 3700X before it, SVI2 maximum core voltage report has captured excursions as high as 1.55V. Even though I'm willing to allow that it has, since AMD has said it's not uncommon, it's both rare and brief enough to have fleetingly minor impact.

I'd be interested to know what reputable data you can reference substantiating a claim of "very high" failure rates for Zen 2 and 3. If you're referring to PowerGPU's experience that's been explained as an outlier because of the way they test their systems.

 

[slybunda]

5800x doesnt boost that high or use those high volts. Its the 5900x and 5950x that hit 1.55v and die.