GPU Server for 500 Concurrent LLM chatbot Users: Sizing Guide
Hardware recommendations for running LLM inference with 500 simultaneous users on dedicated GPU servers.
Quick Recommendation
For 500 concurrent llm chatbot users, we recommend the 2x RTX 5090 (from £358/month) as the starting configuration. High-capacity deployment.
Recommended GPU Configurations
| GPU | VRAM | Monthly Cost | Recommended Models | Notes |
|---|---|---|---|---|
| 2x RTX 5090 | 32 GB | £358/mo | LLaMA 3 70B or Mixtral 8x7B | High-capacity deployment |
| 4x RTX 3090 | 24 GB | £356/mo | 7B models load-balanced | Maximum value at scale |
| 3x RTX 5080 | 16 GB | £327/mo | 7B models with vLLM batching | Balanced cluster |
VRAM & Throughput Requirements
500 concurrent users demand a multi-node GPU cluster. The choice between fewer powerful nodes (2x RTX 5090) and more budget nodes (4x RTX 3090) depends on your model size and latency requirements. For 7B models, the 4x RTX 3090 cluster at £356/month delivers the best aggregate throughput per pound.
Sizing Considerations
500 concurrent users is a large-scale production deployment. At this point, the cost advantage of dedicated hardware over APIs is measured in tens of thousands of pounds per month:
- Cluster topology: Use a load balancer with health checks across 4–6 GPU nodes. Auto-scale based on queue depth and GPU utilisation metrics.
- Model consistency: Ensure all nodes run identical model versions and quantisation configurations for consistent output quality.
- Cost at scale: API providers charge £22,500–£60,000/month for 500 users. A £358/month GPU cluster saves £22,000+ monthly.
- Operational maturity: At this scale, invest in proper monitoring, alerting, and automated deployment pipelines.
Scaling Strategy
At 500 concurrent users, plan for a GPU cluster with 4–6 nodes. Use Kubernetes or a custom orchestrator with auto-scaling based on queue depth.
GigaGPU supports seamless multi-server deployments that scale linearly with your needs.
Cost Comparison
Serving 500 concurrent llm chatbot users via API providers typically costs £22,500-60,000/month depending on usage volume. A dedicated GPU server at £358/month gives you predictable costs with no per-request fees.
500 Users, £358/Month vs. £22,500 on APIs
Deploy a high-capacity GPU cluster for 500 concurrent chatbot users. The savings speak for themselves.
