Lowering idle power on Zen 4?

[rubiconlexicon]

I've been tinkering with my 7700X in an attempt to lower idle power. So far I've shaved 6W off SOC (from ~11W to ~5W) by lowering SOC voltage to 935mV. I also seem to have shaved some extra power off elsewhere by lowering both VDDG voltages to their lowest possible value of 650mV. All of this is stable so far (y-cruncher, CoreCycler, and plenty of time spent at idle waiting for idle crashes). After this I tried messing with VDDP, VDDR_MISC, and even dropping RAM to JEDEC, but none of these reduced power. Have I already done all I can to reduce idle power consumption or is there something else to extract further gains?

 

[AusWolf]

Wait a second... You had a VSOC of just 935 mV with EXPO RAM? Was it stable?

Running my RAM at JEDEC gives me an auto VSOC of 1 V. This is basically the best (and only?) way to decrease idle power as far as I know.

 

[rubiconlexicon]

Wait a second... You had a VSOC of just 935 mV with EXPO RAM? Was it stable?

Running my RAM at JEDEC gives me an auto VSOC of 1 V. This is basically the best (and only?) way to decrease idle power as far as I know.

Indeed, no crashing in y-cruncher, no WHEA errors, no idle or game crashes in multiple days. It is stable. My RAM config is EXPO II, 1.35V on VDD and VDDQ, and 6000MHz on a B650E-F with AGESA 1.2.0.0a fwiw. It does seem that I have a good sample when it comes to SOC voltage.

 

[AusWolf]

Indeed, no crashing in y-cruncher, no WHEA errors, no idle or game crashes in multiple days. It is stable. My RAM config is EXPO II, 1.35V on VDD and VDDQ, and 6000MHz on a B650E-F with AGESA 1.2.0.0a fwiw. It does seem that I have a good sample when it comes to SOC voltage.

Indeed, although I haven't had the courage to try under 1 V with EXPO on mine. It can do 1.2 V without problems. Auto gives me 1.3 V with EXPO (it's way too much), or 1 V at JEDEC (this is what I'm currently on) on my board. Compared to EXPO with auto voltage, this is at least 10 W lower at idle.

 

[jxdking]

Nice cpu that can run soc so low.
To get absolute low idle power, get a 8700G instead. Chiplets design like 7700x wastes lots of energy on communicating between chiplets.

 

[freeagent]

When I run my ram at stock 3200C14 on my 58X3D I run VSOC at .875v

 

[AusWolf]

Nice cpu that can run soc so low.
To get absolute low idle power, get a 8700G instead. Chiplets design like 7700x wastes lots of energy on communicating between chiplets.

Either that, or run your RAM at JEDEC speed and your SoC at 1 V. That lowers power consumption by about 10 W on my system, while the performance loss is non-detectable thanks to the 3D cache and GPU-limit with the 6750 XT.

 

[Launcestonian]

Nice cpu that can run soc so low.
To get absolute low idle power, get a 8700G instead. Chiplets design like 7700x wastes lots of energy on communicating between chiplets.

But the 7700X is a single chiplet design, aka CCD, however agree on the suggestion for 8000 series.

 

[AusWolf]

But the 7700X is a single chiplet design, aka CCD, however agree on the suggestion for 8000 series.

It doesn't matter if it's single or dual CCD. It's the IO die that eats 90-95% of your power at idle, especially with high-speed RAM paired with high MC clock and SoC voltage.

 

[tabascosauz]

It doesn't matter if it's single or dual CCD. It's the IO die that eats 90-95% of your power at idle, especially with high-speed RAM paired with high MC clock and SoC voltage.

Much of the idle power is still unaccounted for by Core or SOC, it's somewhere else, presumably from the actual interconnect outside the dies. This hasn't really changed since Zen 2 - APUs both have the lowest SOC draw and also less of that miscellaneous waste.

Indeed, no crashing in y-cruncher, no WHEA errors, no idle or game crashes in multiple days. It is stable. My RAM config is EXPO II, 1.35V on VDD and VDDQ, and 6000MHz on a B650E-F with AGESA 1.2.0.0a fwiw. It does seem that I have a good sample when it comes to SOC voltage.

Nice results. I think I'm pretty much stuck at 1.0V at the very lowest for 2166FCLK 3000UCLK. 2166 might be causing it to quit any lower than that

Lowering PLL may or may not have had a small difference on AM4. Dunno if it's still there on this platform.

Also not sure if VDDIO_MEM_S3 (the UMC voltage) has an impact on SOC power. Last I checked I think I was running 1.3V VDD, 1.25V VDDQ and 1.25V MEM_S3 for my 6000CL30 profile.

 

[AusWolf]

Much of the idle power is still unaccounted for by Core or SOC, it's somewhere else, presumably from the actual interconnect outside the dies. This hasn't really changed since Zen 2 - APUs both have the lowest SOC draw and also less of that miscellaneous waste.

I don't disagree. I'm just saying that lowering your RAM speed, MC clock and SoC voltage has dramatic effect on your power consumption.

For example, running 4800 instead of 6000 MHz RAM and 1 VSOC instead of 1.3 on my 7800X3D lowers idle power from 30 to 17-18 W. Sure, it doesn't explain where that 18 W comes from, but still...

 

[Zach_01]

Much of the idle power is still unaccounted for by Core or SOC, it's somewhere else, presumably from the actual interconnect outside the dies. This hasn't really changed since Zen 2 - APUs both have the lowest SOC draw and also less of that miscellaneous waste.

Yup, that is exactly the case

Look at my Zen3 having avg Core power 18W and ang SoC power 18W but total (PPT) is 50W
Core+SoC is indeed 36W
There are ~14W on "other" stuff that there is no dedicated sensor.

 

[QuietBob]

The number of memory modules and ranks also affect CPU idle power draw regardless of Vsoc. Here's Zen 2 with 2xSR vs. Zen 3 with 4xSR:

Not quite an apples to apples comparison, since the two systems utilize different RAM and timings. Still, on the 5800X3D minimum SoC power draw is about 5 W higher despite considerably lower voltage.

 

[tabascosauz]

The number of memory modules and ranks also affect CPU idle power draw regardless of Vsoc. Here's Zen 2 with 2xSR vs. Zen 3 with 4xSR:

View attachment 365042View attachment 365043

Not quite an apples to apples comparison, since the two systems utilize different RAM and timings. Still, on the 5800X3D minimum SoC power draw is about 5 W higher despite considerably lower voltage.

Hard to compare like that though across different CPUs. Even samples of the same SKU will vary greatly in SOC power, sometimes even across BIOSes.

 

[sp_00n]

trying to lower my 7700 (non-X) idle wattage and heat in Ghost S1. Managed to do -46 Curve + 83 PBO power limit. Noticed that running EXPO 6000Mhz RAM lowers my R23 cinebench results by 50 and also makes NH-L12GE spin almost 100 rpm faster + idle wattage rises from 22-24 to 27-29. Wonder what would be the way to optimize here. SOC I can set only to OC mode (Asrock B650I lighting board). Any advice?

 

[AusWolf]

trying to lower my 7700 (non-X) idle wattage and heat in Ghost S1. Managed to do -46 Curve + 83 PBO power limit. Noticed that running EXPO 6000Mhz RAM lowers my R23 cinebench results by 50 and also makes NH-L12GE spin almost 100 rpm faster + idle wattage rises from 22-24 to 27-29. Wonder what would be the way to optimize here. SOC I can set only to OC mode (Asrock B650I lighting board). Any advice?

The problem is that enabling expo makes your IMC run faster and with a higher VSOC, which means about +10 W on your CPU package power. It's not good in idle because of the extra heat, and it's not good at full load because that +10 W eats into your CPU package power limit (you have that much less left for the cores). Unless you're running some RAM-intensive program, you'll see a lower all-core performance because of this.

Basically, the 7700 has a power limit of 88 W. If the SOC uses 15 W with expo off, then you have 73 W left for the cores. If you turn expo on, and the SOC eats 28 W, then you only have 60 W left for the cores, which results in lower overall performance.

 

[eidairaman1]

trying to lower my 7700 (non-X) idle wattage and heat in Ghost S1. Managed to do -46 Curve + 83 PBO power limit. Noticed that running EXPO 6000Mhz RAM lowers my R23 cinebench results by 50 and also makes NH-L12GE spin almost 100 rpm faster + idle wattage rises from 22-24 to 27-29. Wonder what would be the way to optimize here. SOC I can set only to OC mode (Asrock B650I lighting board). Any advice?

It would be good to Ask on here

Ryzen Owners Zen Garden

AM5 Epyc Zen4 cpu's even with 3D v-cache is spotted: https://videocardz.com/newz/amd-epyc-4004-zen4-am5-cpus-with-3d-v-cache-have-been-leaked So......just binned Raphael? Literally what Intel did since like 2011 with Xeon E3/E5

www.techpowerup.com

 

[Marcus L]

Why are people so obsessed with lowering which is somewhat a normal idle power consumption for a desktop computer? if you want 5w idle then get a laptop that will throttle under any kind of load and be happy you are saving the planet with a 20-25w power saving which is less than an old style lightbulb, better yet just don't use your computer, 0w=infinity better than 25-30w CPU idle/desktop usage, all the while having a GPU that can munch 300w during gameplay is fine, but god forbid your CPU uses 30w at low load/idle, I am sure Bill Gates and the rest of the climate avengers would be happy to take a private jet trip to your house to tell you how you are causing climate change, cows farting also needs addressing btw

 

[rubiconlexicon]

Why are people so obsessed with lowering which is somewhat a normal idle power consumption for a desktop computer? if you want 5w idle then get a laptop that will throttle under any kind of load and be happy you are saving the planet with a 20-25w power saving which is less than an old style lightbulb, better yet just don't use your computer, 0w=infinity better than 25-30w CPU idle/desktop usage, all the while having a GPU that can munch 300w during gameplay is fine, but god forbid your CPU uses 30w at low load/idle, I am sure Bill Gates and the rest of the climate avengers would be happy to take a private jet trip to your house to tell you how you are causing climate change, cows farting also needs addressing btw

Less heat output and electrical cost as my PC does run most of the day. And I wouldn't say Zen idle power is normal, Intel has seemingly always had around 10W or less idle power on their desktop chips. Nvidia 40 series GPUs which are far larger dies even idle at 10W or below.

 

[Marcus L]

Less heat output and electrical cost as my PC does run most of the day. And I wouldn't say Zen idle power is normal, Intel has seemingly always had around 10W or less idle power on their desktop chips. Nvidia 40 series GPUs which are far larger dies even idle at 10W or below.

I guess if you are just looking at your desktop all day long that makes sense, shall we see how much power consumption Intel CPU's or Nvidia GPU's use when they are actually being used what they are made for? Who uses their desktop PC at idel most of the time? if that was the case then a small form factor low power mini PC or laptop would definitely suit the use case case more than a fully fledged desktop PC, all have their own use case scenarios, do you use a laptop for making calls/texts, checking email and browsing the web when a smartphone will do all of at that and more and fit inside your pocket with a much lower power envelope?

 

[Zach_01]

Less heat output and electrical cost as my PC does run most of the day. And I wouldn't say Zen idle power is normal, Intel has seemingly always had around 10W or less idle power on their desktop chips. Nvidia 40 series GPUs which are far larger dies even idle at 10W or below.

Most of the day is idle or most of the day is running?

My CPU idles around 45W
PC is running about 14-16h per day avg.
But only half of that time is idling. Maybe even less...

Lets say 8 hours. Compared to a CPU that is idling at 10W its 35W more
35W/h = 0.035 KW/h X 8 h = 0.28 KW/h

The cost of my KW/h including vat, taxes and everything is about 0.22€

0.28 KW/h x 365 days = 102.2 KW/h

102.2 KW/h x 0.22€ = 22.5€

+22.5€ per year on my bill for the excessive amount of +35W
oh boy...

 

[chrcoluk]

Yup, that is exactly the case

Look at my Zen3 having avg Core power 18W and ang SoC power 18W but total (PPT) is 50W
Core+SoC is indeed 36W
There are ~14W on "other" stuff that there is no dedicated sensor.

View attachment 365026

Weird how this issue still persists with AMD, 40W idle power for package feels like its a decade behind.

But I wonder how accurate this is, because my AMD system idles at about 30W, measured by wall watt meter, and also now by the smart plug I have it going through, with SSDs running and a few fans (spindles span down state). Although I did tinker with stuff in bios to get it that low, and I have also disabled core performance boost.

 

[Zach_01]

Weird how this issue still persists with AMD, 40W idle power for package feels like its a decade behind.

But I wonder how accurate this is, because my AMD system idles at about 30W, measured by wall watt meter, and also now by the smart plug I have it going through, with SSDs running and a few fans (spindles span down state). Although I did tinker with stuff in bios to get it that low, and I have also disabled core performance boost.

Nothing persists.
Its the nature of modular design. Chiplets.
As long as AMD uses chiplets that is the case. On latest Zen4/5 maybe things improved but still its a thing.

The interconnection between them is "eating" some power

Lets break it down
Total (CPU PPT) package power (avg) 45.5W
Cores: 14W
SoC: 17.8W
Cores+SoC: 31.8W

45.5 - 31.8 = 13.7 =~14

~14W is consumption of the chiplet(s) interconnection.
There is no individual sensor for it. You have to find it like above.

 

[chrcoluk]

Nothing persists.
Its the nature of modular design. Chiplets.
As long as AMD uses chiplets that is the case. On latest Zen4/5 maybe things improved but still its a thing.

The interconnection between them is "eating" some power

View attachment 375611

Lets break it down
Total (CPU PPT) package power (avg) 45.5W
Cores: 14W
SoC: 17.8W
Cores+SoC: 31.8W

45.5 - 31.8 = 13.7 =~14

~14W is consumption of the chiplet(s) interconnection.
There is no individual sensor for it. You have to find it like above.

Yeah I get that, but my Zen 3 system is considerably lower, and I remember that having similar reported idle power, or maybe Zen 3 is officially lower and I am thinking nonsense.

My quoted number is total system power draw, 30W would be impossible if the CPU+SOC is consuming that by itself.

 

[tabascosauz]

Yeah I get that, but my Zen 3 system is considerably lower, and I remember that having similar reported idle power, or maybe Zen 3 is officially lower and I am thinking nonsense.

My quoted number is total system power draw, 30W would be impossible if the CPU+SOC is consuming that by itself.

If you don't have 2CCDs, then your power overall is lower.
Your SOC power floor will be significantly lower (easily sub-10W if you don't choose a wonky board and know some basics on working with VDDCR_SOC), and your "misc" extra power that doesn't fall under cores/SOC will be lower.
2CCD is always fighting an uphill battle, regardless of the generation of CPU.

To be fair, I see the idle power problem as neither a big issue nor a non-issue. Desktops in general are horrible at idle efficiency measured at the wall.