CPU Comparison
Intel Core i7-7820X vs Intel Core i9-7940X
A side-by-side comparison of specs, performance and value. The Intel Core i7-7820X is an 8-core, 16-thread high-end desktop processor on the X299 platform, offering quad-channel DDR4-2666, 28 PCIe 3.0 lanes, and AVX-512 support for workstation and creator workloads.
The Bottom Line
Overview & Launch
Specifications Compared
Performance Compared
Productivity
Strong multi-threaded throughput in CINEBENCH, HandBrake, and similar workloads at launch; still competent for many content creation tasks compared to modern mainstream parts.
Solid multi-threaded performance for its era, though surpassed by modern 12 to 14-core mainstream parts.
Gaming
Delivers high frame rates in 2017-era titles and remains adequate for modern gaming, but newer gaming-focused CPUs with higher clocks and improved IPC pull ahead.
Capable of high-refresh 1080p gaming, but newer mainstream CPUs deliver better frame rates and 1% lows.
Virtualization
PCIe and memory bandwidth are helpful for multiple VMs, but core count is moderate for modern heavy virtualization needs.
Great for home labs and multiple VMs thanks to 14 cores and quad-channel memory.
Efficiency
High 140 W TDP and 14 nm process lead to greater power consumption versus newer 7 nm and smaller nodes.
Very poor efficiency compared to modern architectures, running hot and drawing significant power under load.
Specialized Performance
AI / ML
- No dedicated AI acceleration hardware
- AVX-512 can help certain CPU-bound inference tasks
- Most modern AI workloads are better served by GPUs
- AVX-512 helps with some vector calculations
- No dedicated AI acceleration hardware
- CPU-based inference is significantly slower than modern NPUs or GPUs
Content Creation
Gaming
- Capable of high-refresh gaming with a strong GPU
- Single-core boost reaches up to 4.5 GHz on favored cores
- Modern CPUs offer better gaming efficiency and higher IPC
- High clock speeds help push frames in CPU-bound scenarios
- Mesh architecture adds slight latency compared to ring bus designs
- Lacks the cache size and IPC of modern gaming CPUs
Industry Impact
Best CPU by Use Case
Target Audience
Strengths & Weaknesses
Pros
- 8 cores and 16 threads for multi-threaded workloads
- Quad-channel DDR4 memory increases bandwidth
- 28 PCIe 3.0 lanes plus chipset lanes for expansion
- Turbo Boost Max 3.0 for higher single-core boosts
- AVX-512 support for optimized workloads
- Unlocked multiplier for overclocking
Cons
- High 140 W TDP and power consumption
- No integrated graphics
- Only 28 CPU PCIe lanes, limiting multi-GPU configurations
- Discontinued platform with limited future upgrades
- Older 14 nm process versus modern smaller nodes
Pros
- 14 cores and 28 threads
- 44 PCIe 3.0 lanes for expansive I/O
- Quad-channel DDR4 memory support
- AVX-512 instruction support
- Unlocked multiplier for overclocking
Cons
- Runs extremely hot under heavy loads
- High power consumption for the performance delivered
- Lacks integrated graphics
- Discontinued and outdated platform
- Outpaced by modern mainstream CPUs in efficiency and IPC
Competitors & Alternatives
Intel Core i7-7820X
- AMD Ryzen 7 1800XRival
Creator/Gaming
- AMD Ryzen 7 1700XRival
Creator/Gaming
- AMD Ryzen Threadripper 1920XRival
Workstation
- AMD Ryzen Threadripper 1950XRival
Workstation
- RivalCompare head-to-head
More cores, higher efficiency, and DDR5 on a modern mainstream platform.
Compare head-to-head- AMD Ryzen 9 7900Alt
Strong multi-threaded performance with excellent efficiency.
- AMD Ryzen 9 5900XAlt
12-core AM4 option with strong gaming and creator performance.
High-performance mainstream platform with good upgrade path.
Compare head-to-head- AMD Ryzen Threadripper 2950X (used)Alt
Higher core and lane count for workstation-class workloads.
Intel Core i9-7940X
- AMD Ryzen Threadripper 1950XRival
Workstation
- AMD Ryzen Threadripper 1920XRival
Workstation
- Compare head-to-headIntel Core i9-7960XRival
High-End Desktop
- Compare head-to-headIntel Core i9-7900XRival
High-End Desktop
- Compare head-to-headIntel Core i7-7820XRival
High-End Desktop
Newer Cascade Lake-X alternative on the same platform with better value and refined behavior.
Compare head-to-head- AMD Ryzen 9 5900XAlt
Much more efficient, faster single-core, and relies on a modern AM4 platform.
Massively faster single-core and multi-core performance with modern features at a lower power draw.
Compare head-to-headModern platform with DDR5 and PCIe 5.0, offering vastly superior efficiency.
Compare head-to-headTop-tier modern performance for any workload, leaving the 7940X far behind.
Compare head-to-head
Our Verdict on Each
A competent eight-core HEDT chip with strong multi-threaded performance and platform expansion, though high power draw and limited PCIe lanes compared to higher-tier X299 CPUs make it a niche choice today.
Best for: Used-market upgrade for an existing X299 build with quad-channel DDR4 and a need for more cores than mainstream.
Read the full reviewA potent HEDT processor for its time, the i9-7940X offers strong multi-core capabilities but suffers from high heat output and is outpaced by modern mainstream chips.
Best for: Upgrading an existing LGA 2066 workstation on a tight budget.
Read the full reviewFrequently Asked Questions
Which is faster for gaming, Intel Core i7-7820X or Intel Core i9-7940X?
For gaming, the Intel Core i7-7820X leads with a gaming performance score of 78/100 among Intel Core i7-7820X and Intel Core i9-7940X.
Which uses less power?
The Intel Core i7-7820X has the lowest rated TDP. Power draw across these chips: Intel Core i7-7820X (140 W), Intel Core i9-7940X (165 W).
Do Intel Core i7-7820X and Intel Core i9-7940X use the same socket?
No. They use different sockets (Intel Core i7-7820X: LGA2066, Intel Core i9-7940X: LGA 2066), so each needs a compatible motherboard.
Which has more cores?
The Intel Core i9-7940X has the most cores. Core counts: Intel Core i7-7820X (8 cores), Intel Core i9-7940X (14 cores).