Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Ryzen CPU Voltage explanation
#1
Hi all,
i want to know, if possible, some informations about Ryzen CPU Voltage (i have a 1700X on Asus Prime B350 Plus - all settings to AUTO):
1) what's the difference between CPU Core Voltage SVI2 TFN (under Ryzen 1700x tab) and VDDR CPU (under motherboard tab), and which is correct? Shouldn't be the same?
2) i have seen that MAX CPU VID (not Vcore) for Ryzen CPU is high, 1,550V, i think when XFR is operating. I know that VID is the value imprinted by AMD during fabrication process. Am I correct? Obviously this value is not fixed: minimum is 0.400v.
3) I have seen that in the SENSOR TAB - MAXIMUM Voltage (for both values SVI2 TFN and VDDR CPU) max absolute value is 1.544, or sometimes less, for example 1.504...or 1.525 it depends...i know and i think that these are maximum voltages applied when XFR is operating; i'm afraid that this high voltages can damage my CPU, or reduce lifespan...but this is are the default voltages applied by my motherboard....(it's not a problem related to my motherboard, because it seems that these are the voltages that ASUS is applying as default.) When the CPU is in full load, voltages drop to 1.25, 1.28. Temps are good: during Prime 95 stress test with a Noctua NH-D15 Tdie max temp is 53, TcTl max temp is 73. I know that MAX Tctl is 95, so my temps are more than 20° under maximum limit. My Rig is very stable.
4) I have seen that there are differences about voltages for SVI2 TFN and VDDR CPU: for example minimum voltage for SVI2 TFN is 0.892; minimum voltage for VDDR CPU is 0.392; In full load: SVI2 TFN is 1.23-1.25; VDDR CPU 1.28, 1.30. Why there are these differences?


Thanks a lot!
Reply
#2
CPU Core Voltage (SVI2 TFN) value is the voltage measured by Voltage Regulator, which is supplied to the CPU (as VRM output). This voltage is then reported to CPU and evaluated using telemetry functions.
Vcore or VDDCR CPU is measurement of the same voltage rail, but by the mainboard logic (ITE chip).
I believe the SVI2 TFN values should be more accurate.
The difference between those values can be due to different measurement methods used and their impact on the readout.
VID value of 1.550V (often stuck) is a bug in the CPU firmware that should be fixed with an upcoming AGESA/BIOS update.
Reply
#3
SVI2 only seems to follow P-state transitions, though, while ITE also follow C-state transitions. You never see 0.4ish V on the SVI2 sensor, but do so on the ITE sensor.
Reply
#4
(04-05-2017, 11:29 AM)Martin Wrote: CPU Core Voltage (SVI2 TFN) value is the voltage measured by Voltage Regulator, which is supplied to the CPU (as VRM output). This voltage is then reported to CPU and evaluated using telemetry functions.
Vcore or VDDCR CPU is measurement of the same voltage rail, but by the mainboard logic (ITE chip).
I believe the SVI2 TFN values should be more accurate.
The difference between those values can be due to different measurement methods used and their impact on the readout.
VID value of 1.550V (often stuck) is a bug in the CPU firmware that should be fixed with an upcoming AGESA/BIOS update.

request core voltage by cpu or ite sensor to be include on Summary Windows instead of VID(s?). Seems more important than VID (no fix with current BIOS).
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)