Originally Posted by cssorkinman
25 amps 1 volt = 25 watts - 4.23 calculated lost = 20.77 = 83 % Where did I go wrong?
All graphs for NexFets are for 1.3V. Also for 4GHz most people are using 100 - 110A not 150A.
The quick and dirty way would be > 91% efficiency based on NexFET Power block performance on that graph , for 1.3V only.
Efficiency = Power out /power in = (P_in-P_loss)/P_in = P_out / (P_out+P_loss)
For 150A (25A output current *6 phases), 1.4V the loss would be :
below 4W per phase (per graph figure 1
) x 1.025 normalization factor (figure 8 for 1.4V)
= 4.1W per phase
Power loss for 6 phases = 4.1W x 6 = 24.6W ---> round to 25W
Power out = 1.4V x 150A = 210W
efficiency = 210W/(210+25W) = 0.8936 .... = above 89.3%
Originally Posted by bardacuda
What's the downside? I think the CPU clock limit might be related to droop. If SVI 2 is my drooped voltage then I'm losing like 75mV. I'm hoping a new BIOS fixes it. I've already tried LLC 2 and 3 and they're unstable.
Lower switching frequency results in higher potential ripple. However the X370 prime pro has a rather large capacitor bank. It has over 5K uF at the V_core side , albeit 5k hour rated caps.
Some more possible capacitance ratings:
Warning: Spoiler! (Click to show)
Gigabyte GA-AB350-Gaming 3:
Edited by AlphaC - 5/4/17 at 4:11pm
5KW29 560 6.3V
6 x 560uF= 3,360μF
, http://www.creativecomputing.net/images/AB350-Gaming%203-Rev10-SSBB_LED.jpgAsrock B350 K4
2.5V 820 FX
5x 820 = 4,100μF
It's likely the same for the Asrock B350 Pro4.Asrock X370 Fatal1ty K4
: 6 x 821 = 4,926 uF <_-- "6ZBJ 821 2.5" black capsASUS X370 Prime Pro
: 820 x 8 = 6,560uF <-- 5k life ratingGigabyte K7 / Gaming 5
: capacitors at CPU side are 561 , then 561 x 10 = 5,610uF <-- black caps 10K hr ratingX370 Xpower
has 8x "M 71D" with 560 and 6.3V on the other line (black)
560 x 8= 4,480uFB350 Pro carbon
: M71J 560 6.3V (black)
560x7 = 3920uFB350 Tomahawk
: M71R 560 6.3V
560x7 = 3920uFB350 Mortar
: 5KW12 560 6.3V
560x7 = 3920uF
There's 17 capacitors that read 561 on the X370 Taichi.
I have no idea how many are split to SOC but if we assume that it's 12+4 VRM and use the proportional amount (12 of 16) that would be either 12 or 13 capacitors. A conservative estimate would be 12 x 561uF = 6732uF.Biostar GT7
: 5KW50 820 3V
11 capacitors but likely 8 of the 11 are for CPU based on placement.
Assuming 8x 820 = 6560uF which is very respectableCH VI Hero
's picture at http://www.kitguru.net/wp-content/uploads/2017/03/P1010473.jpg
suggests SOC is at the corner
I count 7x of the ones with 561 and 5x of the ones with 101. I'm not sure how the capacitors are split since it's all bunched up.
7x561 would only be 3,927 but if we include 5x101 you get 4,432uF but I don't want to give any wrong information.Biostar X370 GTN
uses 5KX07 820 3V
so it is likely all 6 for the CPU , 6 x 820 =4,920μF which is very good considering it is ITX