4x GPU 3090 Systems w/ single-PSU

Owned by Joey Houy (Unlicensed)
Last updated: Aug 16, 2022Version comment
2 min read

Intro

Quick look at typical 2000W mATX power supplies input/output spec:

  • 1200W on 100-115Vac

  • 1500W on 115-200Vac

  • 2000W on 200-240Vac

Quick math for 4x GPU systems, for just CPU and GPU’s.

  • 4x 250W and a 250W CPU (AMD Threadripper) = 1250W

  • 4x 350W and a 280W CPU (AMD Threadripper Pro) = 1680W

NVIDIA added dynamic clocking and GPU Clock booster features that allows your GPU’s power consumption to go above and beyond what is advertised, since the GTX 600 series . This feature has been improving through GTX10xx series to the RTX30xx series we use today, and it only gets worse with the next generation of RTX40xx GPU’s that we’ll see in systems soon enough. Although this GPU clock boost sounds great on paper, you will ultimately be limited by power and run into issues with your system that could be frustrating to troubleshoot.

For any 4x GPU single-PSU systems, it is highly recommended you use 200-240V outlet to maximize your GPU performance. If you are using anything but 200-240V, running maximum GPU wattage could trigger your PSU’s circuit protection and cause an abrupt shutdown of the entire system.

Please be mindful of your system’s power input and output limitations to prevent damage to the system’s hardware.

How to limit your NVIDIA GPU’s power limit through nvidia-smi

Before you can set GPU power limitations, you need to make sure all GPU’s have Persistence Mode ENABLED.

nvidia-smi -pm ENABLED

Then you may use the following commands to set a power limitation to all of your NVIDIA GPU’s:

Recommended for 110V outlets (typical US 3-prong outlets)

1200W is pretty exact on the example PSU limitations for 110V I stated above, so you should definitely start here and adjust the wattage up or down depending on what works for you or your building’s outlets/PDU’s.

nvidia-smi -pl 230

4x 230W + 280W = 1200W

Recommended for 115-200V outlets (typical US 3-prong outlets)

nvidia-smi -pl 300

4x 300W + 280W = 1480W

Recommended for 200-240V outlets (typical US 3-prong outlets)

Theoretically there should be no issues, but adding in the dynamic clocking and GPU Clock booster features I mentioned earlier, it might be a good idea to try to set the power limit anyways to prevent any transient power surges from occuring that could still trip your PSU’s circuit protection.

nvidia-smi -pl 350

4x 350W + 280W = 1680W