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
Gaming
Virtualization
Efficiency
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).