F5 BIG-LTM 4000S vs. F5 BIG-LTM 3900-8G-R: A Technical Showdown for High-Performance Load Balancing

Jun 25 , 2025 9

F5 BIG-LTM 4000S vs. F5 BIG-LTM 3900-8G-R: A Technical Showdown for High-Performance Load Balancing

When optimizing application delivery in enterprise environments, F5 Networks’ BIG-LTM series offers scalable solutions tailored to diverse needs. However, selecting between the BIG-LTM 4000S and BIG-LTM 3900-8G-R requires balancing cost, performance, and future scalability. Here’s a detailed analysis to inform your decision.

1. Core Functionalities

Both models deliver robust load balancing and traffic management:

• SSL/TLS Offloading: Accelerate encrypted traffic with dedicated crypto acceleration.

• Traffic Steering: Advanced routing, caching, and compression for optimized workflows.

• Security: Integrated DDoS protection and web application firewall (WAF).

4000S Exclusive Advantages:

• Predictive Analytics: Machine learning-driven insights for proactive scaling.

• Edge Computing Integration: Direct connectivity with F5’s Distributed Cloud services.

• Multi-Tenancy: Isolate workloads with granular partitioning for service providers.

3900-8G-R Focus Areas:

• Cost-Effective Simplicity: Streamlined deployment for small to mid-sized businesses.

• Reliability: Proven track record for stable performance in predictable workloads.

2. Performance Benchmarks

3. Design & Aesthetics

• BIG-LTM 4000S:

• 2U chassis engineered for high-density deployments.

• Redundant fans, power supplies, and network interfaces.

• Modular architecture with up to 8 expansion slots for 100GbE/400GbE cards.

• BIG-LTM 3900-8G-R:

• Compact 1U design with fixed configuration.

• Limited to 4 expansion slots for 10GbE/25GbE ports.

• Streamlined interface with essential LEDs and USB ports.

4. User Experience

• Management Interface:

• Both offer GUI (F5 BIG-IP Configuration Utility) and CLI.

• 4000S adds iControl REST API and Ansible automation for DevOps.

• Troubleshooting:

• 4000S includes LiveDashboard for real-time analytics; 3900 relies on basic logs.

5. Pricing Structure

• BIG-LTM 4000S:

• List Price: 50,000–70,000+.

• ROI: Ideal for enterprises prioritizing scalability and AI-driven optimization.

• BIG-LTM 3900-8G-R:

• List Price: 10,000–15,000.

• Best For: SMBs seeking a reliable, entry-level ADC without advanced features.

6. Battery Consumption

• BIG-LTM 4000S:

• Higher power draw (~1,500W) due to redundancy and advanced hardware.

• ENERGY STAR® certified for efficiency.

• BIG-LTM 3900-8G-R:

• Moderate power consumption (~300W), aligning with eco-friendly budgets.

7. Compatibility & Scalability

• BIG-LTM 4000S:

• Expandable to 32x 100GbE ports and 16x 400GbE ports.

• Configurable with up to 64GB RAM and 8TB NVMe storage.

• BIG-LTM 3900-8G-R:

• Limited to 4x 25GbE ports and 8GB RAM.

• Best for static environments with minimal growth expectations.

8. Software Ecosystem

• BIG-LTM 4000S:

• Runs TMOS 17.x with AI/ML-driven optimizations (e.g., Traffic Steering Advisor).

• Priority access to beta features and extended support contracts.

• BIG-LTM 3900-8G-R:

• Limited to TMOS 16.x with standard feature sets.

• Annual updates focused on security patches.

Final Verdict

• Choose BIG-LTM 4000S If:
  You require extreme scalability, AI-driven insights, and future-proof 400GbE readiness for hybrid cloud architectures.

• Choose BIG-LTM 3900-8G-R If:
  Your environment demands a cost-effective, reliable ADC for straightforward load balancing without advanced customization.

Pro Tip: Invest in the 4000S if your organization plans to adopt edge computing, AI/ML workloads, or 5G edge deployments within 3–5 years.