CPU Comparison
Intel Core i7-5820K vs Intel Core i7-3960X Processor
A side-by-side comparison of specs, performance and value. The Intel Core i7-5820K is a high-end desktop (HEDT) processor built on the Haswell-E architecture. Designed for enthusiasts and professionals, it features six cores and twelve threads, offering a significant multi-threaded performance leap over mainstream quad-core CPUs of its era. Operating at a base frequency of 3.3 GHz and boosting up to 3.6 GHz, it delivers robust computing power for demanding applications. Unlike mainstream chips, it utilizes the LGA 2011-v3 socket and the X99 chipset, supporting quad-channel DDR4 memory for massive memory bandwidth. With 28 PCIe 3.0 lanes, it provides extensive expansion capabilities for multi-GPU setups and high-speed storage arrays. The 140-watt TDP reflects its workstation-class design. While it lacks integrated graphics, requiring a discrete GPU, the 5820K excels in parallel processing tasks like video editing, 3D rendering, and virtualization, making it a powerhouse for creators who need more than standard desktop platforms offer.
The Bottom Line
Overview & Launch
Specifications Compared
Performance Compared
Productivity
6 cores handle rendering well, but lack the speed of modern architectures.
Six cores and Hyper-Threading help in older workloads, though newer CPUs complete multi-threaded tasks much faster and more efficiently.
Gaming
Good for gaming, but single-core speed lags behind modern CPUs.
Playable in many titles at 1080p with a strong GPU, but frame rates and 1% lows fall behind modern processors.
Virtualization
Quad-channel memory and 12 threads make it great for VMs.
Quad-channel memory and 12 threads suit lab or VM setups on legacy hardware.
Efficiency
140W TDP on 22nm is power-hungry by modern standards.
High power draw relative to performance makes it inefficient by today's standards.
Specialized Performance
AI / ML
- No AI hardware
- CPU inference is moderate due to core count
- No dedicated AI acceleration hardware
- Can run basic CPU-based inference, but impractical for modern ML workloads
Content Creation
Gaming
- Can handle modern games with a discrete GPU
- Lower single-core speed limits high-refresh gaming
- Great for multi-tasking while gaming
- Requires strong GPU to mitigate CPU bottlenecks in newer titles
- High-refresh gaming is generally unrealistic
- DDR3 quad-channel does not compensate for low per-core performance
Industry Impact
Best CPU by Use Case
Target Audience
Strengths & Weaknesses
Pros
- 6 cores / 12 threads
- 28 PCIe lanes
- Quad-channel DDR4 memory
- Unlocked for overclocking
Cons
- High 140W TDP
- Older 22nm process
- Only 28 PCIe lanes
- Lacks integrated graphics
Pros
- Six cores and 12 threads offered strong multi-threaded performance in 2011
- Quad-channel DDR3 memory controller
- 40 PCIe lanes from the CPU
- Unlocked multiplier for overclocking
- Still viable for certain legacy workstation workloads
Cons
- No integrated graphics (requires discrete GPU)
- High power consumption for the performance delivered today
- DDR3 limits memory bandwidth compared to DDR4/DDR5 platforms
- PCIe 2.0 instead of 3.0/4.0
- Discontinued platform with limited future upgrade options
Competitors & Alternatives
Intel Core i7-5820K
- AMD Ryzen 7 1700XRival
High-End Desktop
- Intel Core i7-4930KRival
High-End Desktop
- AMD FX-8350Rival
Desktop
- Compare head-to-headIntel Core i7-6800KRival
High-End Desktop
- Compare head-to-headIntel Core i7-5930KRival
High-End Desktop
- AMD Ryzen 5 5600XAlt
Vastly superior single-core speed and efficiency.
- Intel Core i5-12400FAlt
Modern alternative that beats it in almost everything.
- AMD Ryzen 7 5700XAlt
8 cores, better IPC, lower power.
Intel Core i7-3960X Processor
- AMD FX-8150Rival
Enthusiast Desktop
- AMD FX-8350Rival
Enthusiast Desktop
- Intel Core i7-3930KRival
High-End Desktop
- Compare head-to-headIntel Core i7-990XRival
High-End Desktop
- Intel Core i7-4960XAlt
Same LGA2011 platform, higher clocks and Ivy Bridge-E improvements if found used.
Haswell-E HEDT with DDR4 and more PCIe lanes; requires LGA2011-v3 board.
Compare head-to-head- AMD Ryzen 7 5700XAlt
Modern DDR4 platform with far better efficiency and performance.
Our Verdict on Each
A solid entry point into the HEDT market, offering 6 cores and DDR4 support, though aging rapidly compared to modern alternatives.
Best for: Upgrading an existing X99 system for more cores.
Read the full reviewA powerful HEDT chip in its time, the i7-3960X still delivers capable multi-threaded performance for legacy workstations, but it lags far behind modern CPUs in efficiency and per-core speed.
Best for: Upgrading an existing LGA2011 system on a minimal budget to extend its life for specific workloads.
Read the full reviewFrequently Asked Questions
Which is better, Intel Core i7-5820K or Intel Core i7-3960X Processor?
Based on our editorial ratings, the Intel Core i7-5820K comes out ahead with a score of 8/10. That said, the best choice depends on your workload — check the spec and performance breakdown above for gaming, productivity and efficiency differences.
Which uses less power?
The Intel Core i7-3960X Processor has the lowest rated TDP. Power draw across these chips: Intel Core i7-5820K (140 W), Intel Core i7-3960X Processor (130 W).
Do Intel Core i7-5820K and Intel Core i7-3960X Processor use the same socket?
No. They use different sockets (Intel Core i7-5820K: Intel Socket 2011-3, Intel Core i7-3960X Processor: LGA2011 (FCLGA2011)), so each needs a compatible motherboard.
Which is faster in multi-core benchmarks?
The Intel Core i7-5820K posts the highest multi-core benchmark score. Multi-core results: Intel Core i7-5820K (11,000). Benchmark figures are approximate and workload-dependent.