NVIDIA Xid 48. ECC Uncorrectable Memory Error
Xid 48 is NVIDIA's code for uncorrectable GPU memory errors. It crashes training and corrupts model weights. Denpex correlates Xid 48 events with NCCL failures to identify the originating GPU and trigger automated draining.
Xid 48 is NVIDIA's code for uncorrectable GPU memory errors.
What this failure is
NVIDIA Xid 48. ECC Uncorrectable Memory Error is a Hardware failure seen during ML training runs. Xid 48 is NVIDIA's code for uncorrectable GPU memory errors. It crashes training and corrupts model weights. Denpex correlates Xid 48 events with NCCL failures to identify the originating GPU and trigger automated draining. Common tags: Xid, Ecc, Gpu, Hardware.
Is this what broke your run? Paste your log.
You're reading about NVIDIA Xid 48. ECC Uncorrectable Memory Error. Paste your own crash log or traceback below and get the real root cause for YOUR run, not this generic entry. No account, no card. Logs are masked at ingress and never saved to account history.
Want 14 days on the Scale plan?
Request an evaluation code. A verified workplace organization activates up to 50 diagnoses a day, alerts, history, and follow-up questions. No credit card or automatic subscription.
Why it happens (the mechanism)
Single-bit ECC errors accumulate silently until a double-bit ECC error triggers Xid 48. CUDA kernels read corrupted data and propagate errors through the computation. Xid 48 can corrupt model weights mid-training, producing silent data corruption. The failing GPU must be identified and drained immediately. Taken together, these mechanisms explain why the failure is reproducible, why it tends to surface on specific workloads or scales, and why generic mitigation attempts often fall short without addressing the underlying cause.
What you'll observe
- Training job terminates with Xid 48 in dmesg or nvidia-smi
- The same training config works on some GPUs but not others
- Silent data corruption: training continues but produces garbage output
Common symptoms and what they mean
| Symptom | Why it happens |
|---|---|
| dmesg: Xid 48 (hardware damage) on GPU X | Single-bit ECC errors accumulate silently until a double-bit ECC error triggers Xid 48 |
| nvidia-smi -q -d ECC shows non-zero uncorrectable error count | CUDA kernels read corrupted data and propagate errors through the computation |
| Loss degrades silently without an explicit crash as Xid 48 corrupts weights during training | Xid 48 can corrupt model weights mid-training, producing silent data corruption |
| ECC error count increases over time on specific GPUs | The failing GPU must be identified and drained immediately |
Which systems are affected
- Multi-node GPU training with 8+ GPUs per node
- Aging GPU hardware (V100, A100 after heavy use
- Training on PCIe-attached GPUs (more ECC-prone than SXM/NVLink-connected GPUs
- High-utilization clusters running 24/7 training
How to confirm this is the problem
Use this checklist to test the hypothesis against a small reproduction. No single line proves the root cause, so preserve the preceding events and compare one variable at a time.
- ✓Reproduce the failure from a clean checkpoint/seed: the symptom must appear without warm-up state from a previous run.
- ✓Verified signal present: dmesg: Xid 48 (hardware damage) on GPU X
- ✓Verified signal present: nvidia-smi -q -d ECC shows non-zero uncorrectable error count
- ✓Verified signal present: Loss degrades silently without an explicit crash as Xid 48 corrupts weights during training
- ✓Verified signal present: ECC error count increases over time on specific GPUs
- ✓A targeted fix from the "How to fix it" section eliminates or substantially reduces the symptom within one validation pass.
The fix and the prevention pattern
The root cause is on this page and stays free. A free account adds the exact remediation steps, saved history, and the fix on every entry in the encyclopedia.
Sign up free. Unlock the full analysisNo credit card. Daily allowance follows verified trust tier. Instant access.
Xid 48 in context
Xid 48 is one of a small set of codes the NVIDIA driver uses to report GPU faults, and the number is most of the diagnosis: it tells you whether you are looking at your own code, the driver, or a board that needs replacing.
Compare every Xid code side by sideDiagnose this failure in VS Code
Select the traceback or open the failed terminal, then run Denpex locally to see the initiating rank, collateral failures, exact fix, and verification command without uploading the log.
Install the free VS Code extensionRelated failures to investigate next
Root cause
- Single-bit ECC errors accumulate silently until a double-bit ECC error triggers Xid 48
- CUDA kernels read corrupted data and propagate errors through the computation
- Xid 48 can corrupt model weights mid-training, producing silent data corruption
- The failing GPU must be identified and drained immediately
The fix and how to prevent it
Evaluate Denpex on your own logs
Request a Scale evaluation code. A verified workplace organization activates 14 days with up to 50 diagnoses a day. Every account keeps its current diagnosis allowance and gets a verification path. No card or automatic subscription.
Don't just read the fix, diagnose your run
The encyclopedia tells you what went wrong. Denpex tells you what went wrong in YOUR training run. With your logs, your config, and your stack.