Should I Use GPU Cloud Spot Instances in April 2025?

1. The Scheduling Problem

GPU usage is bursty. During model compilation or training, kernels hit 100% utilization; between runs, developers edit code and wait for results. If each program keeps a physical card for its entire lifetime, most hardware sits idle—and idle minutes dominate the bill during prototyping.

2. Spot Instances — Lower Cost via Revocation

Public clouds sell surplus GPUs as spot (pre‑emptible) instances. The discount is deep because the provider can reclaim the VM at any moment to serve full‑price demand.

• Strengths – Ideal for long, checkpointed workloads that tolerate interruption.

• Limitations – Interactive notebooks and short training loops collapse when a spot VM is revoked, and re‑acquiring the same SKU during a capacity squeeze can take minutes to hours. For the newest GPUs (e.g., H100s) spot capacity may not exist at all.

3. Thunder Compute — Lower Cost via Idle‑Time Reuse

Thunder Compute tackles the same cost problem from the opposite direction: instead of interrupting workloads, it squeezes out idle time.

• GPUs are attached to ordinary VMs through lightweight virtualization.

• Allocation is tied to the process, not the VM; when your code finishes, the GPU is returned to a shared pool in seconds.

• No job is ever pre‑empted, so interactive sessions stay up even when demand spikes.

• Because cards spend far less time idle, Thunder needs fewer physical GPUs than concurrently active users—yielding spot‑like pricing with on‑demand predictability.

4. Which Model Fits Prototyping Workloads?

Spot discounts come from shifting risk to you; Thunder’s savings come from cutting waste. For prototyping, guaranteed availability is usually worth more than the larger—but uncertain—spot discount. If you work for a startup, the instability of spot instances is likely a dealbreaker. Check out our Startup-Friendly GPU Cloud Providers for alternatives.

5. Decision Matrix

6. Summary

• Spot instances slash cost by letting the cloud revoke capacity; great when interruptions are acceptable.

• Thunder Compute slashes cost by reclaiming idle time while guaranteeing session continuity.

If your workflow is restart‑tolerant, spot remains the cheapest line item. If you need uninterrupted GPUs but don’t want to pay for idle cards, Thunder’s process‑level scheduling keeps the hardware busy—and your budget lean—without operational surprises.