Ryzen vs Epyc idle power consumption

I am looking to upgrade my home server. Epyc CPUs are pretty cheap on eBay and with the combo of ECC ram and lots of pro motherboard features seems like a no brainer. Unfortunately, It looks like power consumption at Idle is quite different between Epyc and Ryzen.

Does anyone know where this information resides so I can make an educated decision?

2 Likes

Not yet, I have a kWh-meter on order to find out about my EPYC server power consumption.

Epyc boards are not designed with power saving in mind. Epyc is not designed with power savings in mind . There’s no c-states, no sleep, ecc Memory only, the cc’d design uses a lot of power to keep things moving.
I have an epyc Rome 24 core with an ASRock Mobo, 6 dimm slots occupied, the processor idles at 50w, the Mobo adds another 40 (10 gigabit nics included), the rest of the system, a 3070ti, 4nvmes, 2 ssds, 210tb WD reds bring that up to 130-140w constant draw, more when under load …

5 Likes

Both AMD platform’s idle power consumption is less than ideal because of their chiplet based architecture.

AMD’s epyc idle power consumption actually got worse after 2nd generation when they added more chiplets beyond just CCDs to the architecture, despite supporting all the usual C-states.

Very rough estimates for idle power consumption for first and second generation epyc are 50-80w and 75-110w for 3rd generation epyc depending on core count.
Ryzen CPUs are in the 25-40w ballpark depending on core count and also support a few more C-states than epyc.
Aandtech has some articles on AMD’s idle power consumption written by Ian, I’d look there if I wanted more accurate numbers.

1 Like

If you have/do the following on a Zen 3 platform, your idle numbers are going to be a bit high too:

  • use an X570 board
  • Run your RAM faster than DDR4-3200 (slight increase in power between 3200 and 3600)
  • Run your RAM faster than DDR4-3600 (exponential increase between 3600 and 3800, especially with manually tuned tight timings)

With the same 5 VMs doing close to nothing on ESXi, I got the following numbers measured at the wall:

  • i7 4770 + 4* 8GB DDR3-1600 + Asus Z87 Gryphon: 54W
  • i5 12500 + 2* 16GB DDR4-3600 + MSI Z690-A Pro: 50W
  • 5900X + 2* 32GB DDR4-3533 + MSI X570 Tomahawk Wifi: 77W

Common components:
2* SATA SSDs
1* PM951
1* MCX354A-FCBT
500W 80+ Bronze rated PSU (i know…)
2* 80mm fans set to a constant speed using a external PWM controller.

My Intel numbers are a bit high due to the MCX354A-FCBT, it prevents the CPU from idling deeper than C2 state. Both Haswell and Alder Lake platforms can probably idle around 30W with it removed, though I didn’t try so take it with a grain of salt.

Cores do sleep in C6 states with negligible idle power. The I/O die sleeps way less than I would expect but that’s probably because you’re running a hypervisor and a couple of VMs on top of it. Other than that, very nice to hear the numbers about your EPIC.

1 Like

EPYC Rome idle power consumption was frankly a lot less than I was expecting. I have a 7532 and Tyan S8030 with 8x16GB 2666 sitting on my testbench, and booted into Proxmox with a single NVME it idles right around 48W, which is phenomenal given how many cores/PCIE lanes this setup has. Of course once it’s incorporated into a server with NVME/rust/10GbE, that number will jump, but given what I had read I expected even just the CPU/mobo/ram to be closer to 100W than 50W at idle.

4 Likes

Thank you! I ended up going with a 2700x.

Ryzen 2700x
4x Fans
1x 2Tb NVME
4x 12Tb HDD

Averaging 76 Watts over the last 24 hours

3 Likes

Thanks for the update and the numbers

Phoronix tested the new EPYC Siena (specifically the 32 core version with 180W TDP), which is a replacement for the aging Rome SKUs with modern Zen4+DDR5+PCIe5.

This is your new premium home server option. Low idle, cheap SKUs, lots of lanes,RDIMMs,etc.

6 Likes

zen4 epyc genoa is 62 watts plus 2.5 watts per core at load. 63.5 watts at idle with 3 32gb dimms.

2 Likes

That is impressive. the 2600 version of the ipmi chip used in the zen4 servers uses 7 watts. The 2500 version of the ipmi chip used in zen3 and earlier servers uses 25 watts. I don’t know if that is all the time, or just when it is in use.

I got a X570D4U-2L2T with Aspeed 2500 IPMI and it draws 9W from the wall if server is powered down. Can’t say what power consumption is if fans, logs, web UI, etc. are running…because I can’t remove the (on-board)X550 NIC, CPU and memory to test this :wink: But IPMI power is a thing.

2 Likes

My experience with the Aspeed 2500 is indeed ~10W each.

1 Like

EPYC Milan 7713 idle power on a ROMED8-2T board with 4x 16GB DDR4 RDIMMs, dual Intel X550 10GBase-T and one consumer 2280 NVME boot drive is 65W.

6 Likes

Just joined the board based on this thread. Thanks for the info that’s been shared. I’m definitely looking at AMD EPYC for a more modern and less power hungry home server compared to my Dell R620 (and less noise).

1 Like

I was surprised that the idle power is 65 watts. Could you please tell me what the average wattage is?

AMD EPYC 7302 16-Core Processor
256GB DDR4 2400Mhz ECC
Supermicro h11ssl-i
LSI 9305-24i
14x 1.92TB SSD
10x 4TB 7200rpm HDD
1TB samsung 980 NVME
Intel x710-da2
Nvidia Tesla P4
Intel Arc A380

OS: Truenas Scale

Idle ~189-198W (It fluctuates)

2 Likes