CPU Comparison
Intel Core i5-7640X X-series vs Intel Core i7-5820K
A side-by-side comparison of specs, performance and value. The Intel Core i5-7640X is a quad-core, four-thread desktop processor on the LGA2066 platform with base and boost clocks of 4.0 GHz and 4.2 GHz, respectively, dual-channel DDR4-2666 memory, and 16 PCIe 3.0 lanes.
The Bottom Line
Overview & Launch
Specifications Compared
Performance Compared
Productivity
Four cores with no Hyper-Threading limit multi-threaded workloads; better suited to light productivity than heavy rendering or compiling.
Solid performance for older software and moderate rendering tasks, but falls behind modern 6-core CPUs in IPC and clock speed.
Gaming
Sufficient for high-refresh gaming when paired with a strong GPU, but constrained by lack of Hyper-Threading and limited core count in modern titles.
Playable in modern esports and AAA titles when paired with a strong GPU, but likely to bottleneck top-tier cards in CPU-intensive scenarios.
Virtualization
Can run modest VM loads, but core and thread count make it less ideal for multiple concurrent VMs.
Excellent value for home labs due to high core count, VT-d support, and PCIe lane availability for multiple NICs or storage controllers.
Efficiency
High 112 W TDP for a quad-core design results in lower performance-per-watt than newer mainstream platforms.
High power consumption (140W TDP) and heat output compared to 14nm, 10nm, or 7nm counterparts.
Specialized Performance
AI / ML
- No dedicated AI acceleration; CPU-bound inference only.
- Lacks AVX-512; limited to SSE4.1/4.2 and AVX2 instruction sets.
- No dedicated AI or matrix acceleration hardware.
- AVX2 support offers some vector compute capability.
Content Creation
Gaming
- High clocks help in CPU-bound scenarios, but modern games increasingly benefit from more cores/threads.
- Requires a discrete GPU; no integrated graphics.
- Performance comparable to contemporary mainstream Kaby Lake i5s when GPU-bound.
- Requires discrete graphics; no integrated GPU.
- PCIe 3.0 lanes limit full potential of modern RTX 40-series GPUs.
- Boost clocks are modest by modern standards.
Industry Impact
Best CPU by Use Case
Target Audience
Strengths & Weaknesses
Pros
- High base and boost clock speeds
- Unlocked multiplier for overclocking
- Supports Intel Optane Memory
- VT-x and VT-d virtualization support
- DDR4-2666 dual-channel memory support
Cons
- No integrated graphics requires a discrete GPU
- No Hyper-Threading; only four threads
- Only dual-channel memory on a HEDT platform
- Only 16 CPU PCIe 3.0 lanes
- Discontinued platform with limited upgrade options
Pros
- Relatively low entry cost for a used HEDT platform
- Quad-channel DDR4 memory support
- 28 PCIe lanes allow for multiple expansion cards
- Unlocked for overclocking
- Strong multi-core performance for its era
Cons
- High power draw and heat output
- No integrated graphics
- Limited to 28 PCIe lanes (fewer than 5930K/5960X)
- Requires expensive X99 motherboards and DDR4 RAM
- Older architecture lacks modern instruction sets like AVX-512
Competitors & Alternatives
Intel Core i5-7640X X-series
- AMD Ryzen 5 1600Rival
Mainstream
- AMD Ryzen 5 1500XRival
Mainstream
- Intel Core i5-7600KRival
Mainstream
- Intel Core i7-7700KRival
Mainstream
- Intel Core i7-7740XRival
HEDT
- Intel Core i5-8400Alt
Six-core mainstream Coffee Lake with better multi-threaded performance.
- AMD Ryzen 5 2600Alt
Six cores, 12 threads on AM4 with superior efficiency and upgrade path.
- Intel Core i5-9600KAlt
Later-generation six-core with higher clocks and improved platform longevity.
- AMD Ryzen 5 3600Alt
Zen 2 six-core with much higher IPC and efficiency on AM4.
- Intel Core i5-10600KAlt
Six-core, 12-thread Comet Lake on modern platform with DDR4 and better connectivity.
Intel Core i7-5820K
- AMD Ryzen 5 1600Rival
Mainstream
- AMD Ryzen 7 1700Rival
Creator
- Intel Core i7-4790KRival
Gaming
- AMD FX-9590Rival
Enthusiast
- Compare head-to-headIntel Core i7-6800KRival
Workstation
If you need the full 40 PCIe lanes for tri-SI or heavy storage arrays.
Compare head-to-head- AMD Ryzen 5 5600Alt
A modern, significantly faster and more efficient gaming CPU.
- Intel Core i5-12600KAlt
Modern platform with PCIe 5.0 and DDR5 support.
- AMD Ryzen 9 5900XAlt
Massive multi-core performance jump for content creation.
More cores and higher frequency on a still-recent mainstream platform.
Compare head-to-head
Our Verdict on Each
A capable but ill-positioned quad-core for the X299 HEDT platform, offering strong clock speeds yet lacking Hyper-Threading, integrated graphics, and the multi-threaded punch of contemporaries; mainly relevant today for specific upgrades or used-market builds.
Best for: Upgrading an existing X299 system on a tight budget or acquiring used parts at low cost
Read the full reviewThe i7-5820K was a groundbreaking value proposition in 2014, bringing DDR4 and quad-channel memory to a lower price point. Today, it remains viable only for budget builds, handicapped by high power consumption and limited PCIe lanes compared to modern standards.
Best for: Building a budget-friendly used workstation for virtualization or light content creation.
Read the full reviewFrequently Asked Questions
Which is better, Intel Core i5-7640X X-series or Intel Core i7-5820K?
Based on our editorial ratings, the Intel Core i7-5820K comes out ahead with a score of 7.5/10. That said, the best choice depends on your workload — check the spec and performance breakdown above for gaming, productivity and efficiency differences.
Which is faster for gaming, Intel Core i5-7640X X-series or Intel Core i7-5820K?
For gaming, the Intel Core i5-7640X X-series leads with a gaming performance score of 72/100 among Intel Core i5-7640X X-series and Intel Core i7-5820K.
Which uses less power?
The Intel Core i5-7640X X-series has the lowest rated TDP. Power draw across these chips: Intel Core i5-7640X X-series (112 W), Intel Core i7-5820K (140 W).
Do Intel Core i5-7640X X-series and Intel Core i7-5820K use the same socket?
No. They use different sockets (Intel Core i5-7640X X-series: FCLGA2066, Intel Core i7-5820K: FCLGA2011-3 (LGA2011-v3)), so each needs a compatible motherboard.
Which has more cores?
The Intel Core i7-5820K has the most cores. Core counts: Intel Core i5-7640X X-series (4 cores), Intel Core i7-5820K (6 cores).