GPU Server for 250 Concurrent Voice agent Users: Sizing Guide
Hardware recommendations for running real-time STT + TTS pipeline with 250 simultaneous users on dedicated GPU servers.
£358/month for an Enterprise Voice Platform
Two hundred and fifty concurrent voice sessions is enterprise territory. The typical API bill at this scale lands between £399 and £399/month across STT, LLM, and TTS providers. A 2x RTX 5090 cluster on GigaGPU delivers the same throughput for £399/month — saving your organisation £130,000-£355,000 annually while keeping every conversation private on your own infrastructure.
Enterprise Cluster Options
| GPU | VRAM | Monthly Cost | Recommended Models | Notes |
|---|---|---|---|---|
| 2x RTX 5090 | 32 GB | £399/mo | Distributed STT + LLM + TTS | Enterprise voice platform |
| 3x RTX 5080 | 16 GB | £189/mo | Whisper + LLM + TTS cluster | Balanced voice cluster |
Distributed Pipeline Architecture
At 250 concurrent sessions, the voice pipeline (Whisper ~3 GB, LLM 4-8 GB, TTS 2-4 GB) runs as a distributed system across multiple GPUs. The recommended approach: dedicate specific nodes to specific pipeline stages. One RTX 5090 handles all STT and LLM processing, while the second focuses on TTS generation and audio streaming.
With 250 active sessions, expect 75-100 active GPU inference tasks at any moment. Natural conversation patterns mean users alternate between speaking and listening, creating a workload that peaks and troughs continuously. Design for the P95 peak, not the theoretical maximum.
Enterprise Engineering Requirements
- Geographic distribution: If your users span multiple regions, deploy GPU nodes in each region. A 150ms round-trip to a distant data centre breaks the conversational illusion. GigaGPU’s UK hosting works excellently for European deployments.
- High availability: At 250 users, downtime is unacceptable. Run N+1 redundancy — if your workload needs 2 GPUs, provision 3. The cost of the spare node (£109-£179/month) is trivial compared to the revenue impact of an outage.
- Compliance and recording: Many enterprise voice deployments require call recording. Process recordings on-GPU for transcription rather than streaming to a third-party service. Your dedicated hardware handles both real-time and batch transcription.
- Model versioning: Deploy new model versions to one node at a time. Route a percentage of traffic to the new version, validate quality metrics, then roll out fully. Blue-green deployment for voice agents.
Cluster Growth Strategy
At 250 concurrent users, deploy a GPU cluster with 3+ nodes. Use Kubernetes or a custom orchestrator with auto-scaling based on active session count and P95 latency. When latency trends above 500ms, automatically provision additional capacity.
GigaGPU supports seamless multi-server deployments. Start with the minimum viable cluster and scale node-by-node as your voice platform grows.
The Strategic Financial Case
API costs at 250 concurrent voice users: £11,250-£30,000/month. Dedicated GPU cluster: £327-£358/month. Annual savings: £130,704-£355,704. At this level, the savings are not incremental — they fundamentally change your unit economics and make voice-first products commercially viable.
Build Your Enterprise Voice Platform
250 concurrent voice agents on dedicated GPU infrastructure. Enterprise scale, startup pricing, complete data sovereignty.
