GPU Server for 50 Concurrent LLM chatbot Users: Sizing Guide
Hardware recommendations for running LLM inference with 50 simultaneous users on dedicated GPU servers.
Quick Recommendation
For 50 concurrent llm chatbot users, we recommend the RTX 3090 (from £89/month) as the starting configuration. Solid mid-range option.
Recommended GPU Configurations
| GPU | VRAM | Monthly Cost | Recommended Models | Notes |
|---|---|---|---|---|
| RTX 3090 | 24 GB | £89/mo | LLaMA 3 8B or Mistral 7B | Solid mid-range option |
| RTX 5080 | 16 GB | £109/mo | 7B models with INT8 quantisation | Higher throughput per request |
| RTX 5090 | 32 GB | £179/mo | Mixtral 8x7B or LLaMA 3 70B (INT4) | Premium single-GPU option |
VRAM & Throughput Requirements
50 concurrent chatbot users push a single GPU toward its limits. Plan for 2–3 GPUs with load balancing, or use a high-VRAM card like the RTX 5090 with aggressive quantisation and optimised batching.
Continuous batching via vLLM is non-negotiable at this scale. Target under 500ms time-to-first-token for acceptable user experience.
Sizing Considerations
At 50 concurrent users, you are running a serious production deployment. Multi-GPU configurations start to make sense:
- Multi-GPU planning: A single GPU can handle 50 users with aggressive batching, but two load-balanced GPUs provide better latency and redundancy.
- Session affinity: For multi-turn conversations, route returning users to the same GPU to leverage cached KV state.
- Queue management: Implement priority queuing to ensure premium users or time-sensitive requests get processed first.
- Failover: At this user count, downtime is visible. Consider redundant GPU nodes for high availability.
Scaling Strategy
A multi-GPU setup is recommended at 50 users. Use load balancing across 2–3 GPUs with session affinity for consistent performance.
GigaGPU supports seamless multi-server deployments. Start with the minimum viable configuration and scale horizontally as traffic grows.
Cost Comparison
Serving 50 concurrent llm chatbot users via API providers typically costs £2,250-6,000/month depending on usage volume. A dedicated GPU server at £89/month gives you predictable costs with no per-request fees.
Scale to 50 Concurrent Users
Deploy dedicated GPU servers for 50 concurrent chatbot users. Fixed pricing, no per-request charges, enterprise-ready.
