Originally Posted by Falkentyne
You are correct in some of your points. Extreme LLC should simply not be used at those voltages. Extreme Loadline calibration is 0.2 mOhms and Turbo is 0.4 mOhms and High is 0.8 mOhms. In "general", if you can get away with it, MORE vdroop is better for you, not less. But on fixed voltages, since AC Loadline won't help you (see below for full explanation), you need a balance between bios voltage and vdroop.
First of all, the below is based on "Auto" vcore being used, NO VRM loadline calibration used (Intel specified VRM loadline used-1.6 mOhms), and x49/x50 core multiplier, with AC Loadline limited to 1.6 mOhms.
The entire problem with the "1.520v" value is, the way Intel designs these processors (based on *AUTO* Vcore and Serial VID), it will *never* see a 1.52v idle voltage, with zero amps anyway. If you use the maximum AC Loadline of 1.6 mOhms (I found that at 4.9 and 5 ghz default VIDS, there is no difference in load VR VOUT between an ACLL of 1.6 mOhms and ACLL of 1.3 mOhms except at light loads), and use Auto vcore (x50 and x49 multiplier), your idle VR VOUT would be about 1.40v, not 1.520v. That's because the AC Loadline value is what is responsible for boosting the "Idle" voltage target and the "load" voltage target to the VRM. The "base" VID at x49 and x50 multiplier is about 1.175v to 1.250v, depending on the silicon quality of your processor. (you can get this value manually, on fixed voltage, by setting AC Loadline and DC Loadline to "1" (0.01 mOhms)). If you were using pure auto vcore at this point, and NO loadline calibration (LLC Standard/Normal), this is the Voltage "target" that would get sent to the VRM, and used by the voltage controller before vdroop.
An AC Loadline higher than 1 will raise the default idle voltage up. An AC Loadline of 1.60 (160) will put the idle VR VOUT somewhere around 1.40v. An AC Loadline of 2.10 (maximum Intel allows for 4/6 core processors) will put the idle VR VOUT at about 1.45v.
DC loadline affects the VID *AFTER* the VRM already has the voltage ID target programmed--meaning the DC Loadline has no effect on VR VOUT at all. The DC Loadline mOhms resistance value affects the VID in the exact same way that "VRM Loadline" (Loadline calibration) affects VR VOUT. However Intel specifies that DC Loadline is only used for power reporting, not for the CPU power supply. CPU Package Power is the result of VID * Amps, after DC Loadline affects the VID.
(Vdroop in millivolts is equal to R * I, based on Ohm's law...R=resistance (milliohms), I=Current (Amps).
At full load, the AC Loadline will boost the CPU VRM voltage target even higher than it does at idle. This VRM target cannot exceed 1.520v, but *will* be up to 1.520v on auto voltages. (easy way to see this safely on your own? Set AC Loadline to 160 and DC Loadline to 1, and watch the VID in windows. DC Loadline=1 prevents DC Loadline from dropping the VID for power reporting).
Now, this is where NOT having loadline calibration will help your processor's longevity. That 1.520v (1520mv) will be dropped by the VRM loadline value (in this case default is 1.6 mOhms), depending on resistance, so anywhere between 1.220v to 1.30v at full load, depending on amps.
Intel uses AC Loadline to help 'mitigate excessive vdroop' without needing high idle voltages, by raising the VRM voltage target at full load.
Dropping AC loadline below 1.6 mOhms (160) will reduce the idle VR VOUT in windows. Load VR VOUT (heavy amps) will remain the same depending on if AC Loadline is lowered slightly or a lot, because again this is a factor of resistance. You will have to lower AC loadline quite a bit to have the "VRM target" at full load below 1.520v, which will then drop your load VR VOUT also.
These settings are intel's maximum limits.
Now to answer your question, the problem with using 1.52v set in BIOS with NO loadline calibration at all, is that when you use a fixed voltage, AC Loadline can no longer help you. Fixed vcore bypasses AC Loadline and programs the VRM manually with a new voltage target. So your VR VOUT is going to be extremely high--probably 1.49v. You are not going to like that and even if it "may" be safe if NO LLC is used, you would not want to see slow degradation anyway. It makes far more sense just to use 1.3 mOhms AC Loadline or 1.6 mOhms AC Loadline (130-160) and use pure Auto vcore, and NO LLC, and get a lower idle voltage. It just makes sense.
Note: SVID Offset being enabled disables all manual and offset voltage control and allows VID to exceed 1.520v, by up to 200mv.
This can be useful to people on subzero, but a neat trick, since AC Loadline can now boost VID VRM target higher than 1520mv, is to lower AC loadline by a lot (like, 80-110, depending on your CPU quality) and then enable SVID offset. The lower AC Loadline will reduce your idle vcore by a lot, and SVID Offset enabled will allow VID VRM to exceed 1.520, but due to the lower AC Loadline, it will drop back down to 1520mv, then vdroop (VRM loadline) will drop it much lower on load.
Not sure if this makes sense. Your best bet is to actually test these things.
WARNING: NEVER enable SVID OFFSET ON AUTO VCORE if AC LOADLINE IS 1.6 MOHMS OR HIGHER! YOUR VR VOUT WILL BE TOO HIGH FOR SAFE AMPS LIMITS.
Okay so a little confusing. I dropped the LLC to auto. Dropped the VCORE to auto. Manually set the AC to 1.6 and DC to 1. It does not hit 1.52v anywhere and it does allow me to clock up to 5.2ghz with decent voltages, BUT, benchmark scores go DOWN, and I mean WAYYYYY Down. Not sure what math I am supposed to be calculating for correct voltages when messing with AC and DC and where to really move the testing