CPU Comparison
Intel Core i7-6800K vs Intel Core i9-9940X
A side-by-side comparison of specs, performance and value. The Intel Core i7-6800K is a six-core, 12-thread HEDT processor on the X99 platform, offering quad-channel DDR4, 28 PCIe 3.0 lanes, and Turbo Boost Max 3.0 for creators and enthusiasts who need more I/O than mainstream desktops.
The Bottom Line
Overview & Launch
Specifications Compared
Performance Compared
Productivity
Gaming
Virtualization
Efficiency
Specialized Performance
AI / ML
- No dedicated NPUs or matrix accelerators
- Suitable for CPU-bound inference workloads only
- AVX2 support helps in some compute-heavy tasks
- No dedicated AI accelerators; relies on AVX‑512 CPU inference.
- Acceptable for light CPU‑based inference or prototyping, but not competitive with modern CPUs or GPUs with DL Boost / Tensor cores.
Content Creation
Gaming
- Handles high-refresh gaming with a capable GPU
- Turbo Boost Max 3.0 can aid lightly threaded titles
- Modern CPUs typically deliver higher gaming efficiency
- Strong single‑core clocks up to 4.4 GHz with Turbo Boost Max 3.0 up to 4.5 GHz on favored cores.
- Capable of 144 fps+ esports performance at 1080p with a modern GPU; more GPU‑bound at 1440p and 4K.
- Modern 6–8 core CPUs often match or beat it in games while drawing far less power.
Industry Impact
Best CPU by Use Case
Target Audience
Strengths & Weaknesses
Pros
- Six cores and 12 threads remain viable for productivity
- Quad-channel DDR4 provides strong memory bandwidth
- 28 PCIe 3.0 lanes enable multi-GPU and NVMe flexibility
- Unlocked multiplier for overclocking enthusiasts
- Turbo Boost Max 3.0 improves lightly threaded performance
Cons
- 140 W TDP is high by modern standards
- No integrated graphics requires a discrete GPU
- X99 platform is legacy with limited future CPU options
- PCIe lane count lower than 40-lane Broadwell-E SKUs
- Launch price higher than newer, more efficient options
Pros
- 14 cores and 28 threads for heavily threaded workloads.
- 44 PCIe 3.0 lanes for multi‑GPU and NVMe setups.
- Quad‑channel DDR4‑2666 with up to 128 GB support.
- AVX‑512 instruction support for specialized compute.
- Unlocked multiplier for enthusiast overclocking.
Cons
- High 165 W TDP and relatively low efficiency vs newer CPUs.
- Older 14 nm Skylake‑X platform with no upgrade path beyond Cascade Lake‑X.
- No integrated graphics; requires a discrete GPU.
- Only 44 PCIe lanes versus 64 on competing Threadripper platforms.
- Discontinued, with limited long‑term platform support.
Competitors & Alternatives
Intel Core i7-6800K
- AMD Ryzen 5 1600XRival
Mainstream Desktop
- AMD Ryzen 7 1700Rival
Creator
- AMD Ryzen 7 1800XRival
Enthusiast
- Intel Core i7-6700KRival
Mainstream Gaming
- Compare head-to-headIntel Core i7-5820KRival
Previous-Gen HEDT
- Intel Core i7-7820XAlt
More cores and higher PCIe lane count on the newer X299 platform.
- AMD Ryzen 7 5800XAlt
Much higher single-thread performance and efficiency on AM4.
- AMD Ryzen 9 5900XAlt
12 cores and 24 threads with strong performance per watt.
- Intel Core i7-14700KAlt
Modern DDR5 platform with more cores and features for new builds.
- AMD Ryzen 9 7950XAlt
Cutting-edge multi-threaded performance and PCIe 5.0 support.
Intel Core i9-9940X
- AMD Ryzen Threadripper 2920XRival
HEDT / Workstation
- AMD Ryzen Threadripper 2970WXRival
HEDT / Many‑Core Workstation
- AMD Ryzen 9 3900XRival
High‑End Mainstream / Creator
- Compare head-to-headIntel Core i9-10940XRival
HEDT (Cascade Lake‑X)
- Compare head-to-headIntel Core i9-7940XRival
Previous‑Gen HEDT
- Intel Core i7-14700KAlt
Newer hybrid architecture with similar or better multi‑thread performance and far better efficiency for a new build.
- AMD Ryzen 9 7900Alt
Modern AM5 platform with DDR5 and PCIe 5.0, much better efficiency, and strong creator performance.
Our Verdict on Each
A capable entry point into X99 HEDT with solid multi-threading and PCIe headroom, now best suited to budget used builds or specialized workloads rather than new gaming rigs.
Best for: Budget-conscious used HEDT build for multi-threaded workloads
Read the full reviewA capable HEDT CPU with strong multi‑threaded performance and excellent I/O, but outclassed in efficiency and value by newer mainstream and HEDT alternatives.
Best for: Used or discounted X299 workstation builds where you need many cores and PCIe lanes on a budget.
Read the full reviewFrequently Asked Questions
Which uses less power?
The Intel Core i7-6800K has the lowest rated TDP. Power draw across these chips: Intel Core i7-6800K (140 W), Intel Core i9-9940X (165 W).
Do Intel Core i7-6800K and Intel Core i9-9940X use the same socket?
No. They use different sockets (Intel Core i7-6800K: LGA2011-v3, Intel Core i9-9940X: FCLGA2066), so each needs a compatible motherboard.
Which has more cores?
The Intel Core i9-9940X has the most cores. Core counts: Intel Core i7-6800K (6 cores), Intel Core i9-9940X (14 cores).