GPU Server for 100 Concurrent LLM chatbot Users: Sizing Guide
Hardware recommendations for running LLM inference with 100 simultaneous users on dedicated GPU servers.
Quick Recommendation
For 100 concurrent llm chatbot users, we recommend the 2x RTX 3090 (from £178/month) as the starting configuration. Cost-effective scaling.
Recommended GPU Configurations
| GPU | VRAM | Monthly Cost | Recommended Models | Notes |
|---|---|---|---|---|
| 2x RTX 3090 | 24 GB | £178/mo | LLaMA 3 8B load-balanced | Cost-effective scaling |
| RTX 5090 | 32 GB | £179/mo | Mixtral 8x7B | High throughput single node |
| 2x RTX 5080 | 16 GB | £218/mo | 7B models load-balanced | Balanced price/performance |
VRAM & Throughput Requirements
100 concurrent users require serious compute. Two load-balanced RTX 3090s at £178/month give you 48 GB of total VRAM and ~190 tok/s aggregate throughput. Alternatively, a single RTX 5090 can handle the load with its 32 GB VRAM and superior batching performance.
Continuous batching, INT8 quantisation, and optimised KV cache management are all essential at this scale.
Sizing Considerations
100 concurrent users is enterprise territory. The infrastructure decisions you make here directly impact user experience and operational costs:
- Distributed architecture: Two GPUs with load balancing provide better latency distribution and fault tolerance than a single high-end card.
- Memory bandwidth: At 100 users, memory bandwidth often becomes the bottleneck before compute. The RTX 5090’s higher bandwidth gives it an edge for concurrent serving.
- Cost optimisation: 2x RTX 3090 (£178/mo) and 1x RTX 5090 (£179/mo) cost nearly the same but offer different trade-offs: redundancy vs. simplicity.
- Monitoring and alerting: Implement GPU utilisation, queue depth, and latency monitoring to catch degradation before users are affected.
Scaling Strategy
A multi-GPU setup is recommended at 100 users. Use load balancing across 2–3 GPUs with session affinity for consistent performance.
GigaGPU supports seamless multi-server deployments. Scale horizontally with identical GPU nodes as your user base grows.
Cost Comparison
Serving 100 concurrent llm chatbot users via API providers typically costs £4,500-12,000/month depending on usage volume. A dedicated GPU server at £178/month gives you predictable costs with no per-request fees.
Enterprise Chatbot at £178/Month
Deploy multi-GPU infrastructure for 100 concurrent chatbot users. Predictable costs vs. £4,500+ on API providers.
