---
title: Checking Node CPU and Memory Speed
slug: checking-node-cpu-and-memory
description: How to use a live Ubuntu USB and sysbench to measure memory bandwidth on a node, plus the firmware and BIOS fixes for known underperforming configurations.
tags:
  - node-provider
  - maintenance
  - runbook
  - firmware
date: 2026-05-04
related:
  - node-provider-maintenance
  - updating-node-firmware
  - node-hardware-guide
  - node-provider-troubleshooting
---

A node that is running but failing block-maker checks is sometimes
suffering from a hardware-level performance problem — a buggy
firmware revision, a marginal power supply, or a power-redundancy
configuration that throttles the CPU. The fastest way to confirm or
rule that out is to boot a live Ubuntu USB on the affected machine
and run a memory-bandwidth benchmark.

> [!WARNING]
> Use a **live** Ubuntu USB image — do not run the installer
> and do not let it touch the disks. Wiping the IC-OS install would
> force a full redeployment.

## Run the test

1. Power the node off through the BMC (see *Powering down via the
   BMC* below).
2. Insert a live Ubuntu USB stick and boot from it — choose
   *Try Ubuntu*, not *Install*.
3. Open a terminal and install `sysbench`:

   ```bash
   sudo apt update
   sudo apt install sysbench
   ```

4. Run the memory benchmark:

   ```bash
   sysbench --test=memory run
   ```

5. Read the *transferred* line at the end of the output. Healthy
   nodes should report at least **5.6 GB/s** of memory throughput.

A result well below that threshold — say, 2.6 GB/s —
points at a hardware or firmware problem rather than software.

## Known issues and fixes

### Dell PowerEdge

Some Dell PowerEdge nodes have shipped with a CPLD firmware revision
that caps memory bandwidth around 2.6 GB/s. Updating the CPLD
firmware restores full performance. See
[Updating Firmware](/wiki/updating-node-firmware/) for how to obtain
and apply Dell firmware packages.

### Supermicro

Two fixes have helped on Supermicro nodes:

- **Power-cycle the chassis.** A clean cold start sometimes clears
  the throttle.
- **Disable an NUMA-related BIOS option.** Enter BIOS and navigate
  to **Advanced > ACPI Settings > ACPI SRAT L3 Cache As NUMA Domain**,
  then set it to **Disabled**.

## Powering down via the BMC

> [!TIP]
> When servicing a PDU or running power-side diagnostics, power the
> attached servers down through the BMC first. Yanking power on a
> live IC-OS install can leave the node in a state that needs
> recovery.

Use the BMC web UI or `ipmitool` from a separate workstation to
issue a graceful shutdown.

## Related

- [Node Provider Maintenance Guide](/wiki/node-provider-maintenance/) — the parent runbook.
- [Updating Firmware](/wiki/updating-node-firmware/) — the typical fix when the benchmark fails.
- [Node Provider Machine Hardware Guide](/wiki/node-hardware-guide/) — baseline expectations for node hardware.
- [Node Provider Troubleshooting](/wiki/node-provider-troubleshooting/) — the broader troubleshooting index.