CPU Comparison
Intel Core i5-655K vs Intel Core i5-680
A side-by-side comparison of specs, performance and value. The Intel Core i5-655K is an unlocked dual-core Clarkdale processor launched in May 2010, offering BCLK multiplier freedom for enthusiast overclockers on the LGA 1156 platform.
The Bottom Line
Overview & Launch
Specifications Compared
Performance Compared
Productivity
Two cores are fundamentally insufficient for any modern productivity workload.
Best single-threaded performance in Clarkdale but still insufficient for modern productivity.
Gaming
Even overclocked, the dual-core architecture and weak iGPU make modern gaming impossible.
High clock speed helps slightly but the dual-core design remains a fundamental barrier.
Virtualization
Minimal utility with only two cores and 4GB-friendly memory limits.
Two cores with Hyper-Threading remain inadequate.
Efficiency
73W base TDP increases significantly when overclocked, resulting in poor efficiency.
73W for 3.6GHz on 32nm was reasonable for 2010 but poor by modern standards.
Specialized Performance
AI / ML
- No AI acceleration capabilities
- Completely unsuitable for any machine learning task
- No AI acceleration
- Unsuitable for any ML workload
Content Creation
Gaming
- Overclocking does not overcome the dual-core limitation
- HD Graphics at 733MHz cannot handle any modern 3D workload
- Was marginal for 2010 gaming even with a discrete GPU
- 3.6GHz clock cannot compensate for two cores in modern games
- 733MHz HD Graphics far too weak for 3D rendering
- Even with a discrete GPU in 2010, quad-cores were preferable
Industry Impact
Best CPU by Use Case
Target Audience
Strengths & Weaknesses
Pros
- Unlocked multiplier was rare and valuable for LGA 1156 overclocking
- 32nm process allowed impressive frequency headroom
- Interesting piece of Intel's overclocking history
- BCLK-independent overclocking simplified tuning
Cons
- Only two cores even when overclocked
- More expensive than the identical-performance i5-650 at launch
- Clarkdale's dual-die design limited memory controller performance
- No practical use in modern computing
- Overclocking a dual-core provides negligible real-world benefit today
Pros
- Fastest Clarkdale processor ever made
- 3.866GHz turbo boost was impressive for 2010
- Maintained 73W TDP despite high clocks
- Strong single-threaded legacy performance
- Interesting piece of Intel frequency scaling history
Cons
- $294 price was exorbitant for two cores
- Dramatically outperformed in multi-threaded tasks by the $176 i5-750
- No AVX support
- Weak 733MHz integrated graphics
- Completely obsolete for any modern use
Competitors & Alternatives
Intel Core i5-655K
- AMD Phenom II X2 560 Black EditionRival
Unlocked Dual-Core
- AMD Phenom II X4 955 Black EditionRival
Unlocked Quad-Core
- Compare head-to-headIntel Core i5-750Rival
Mainstream Quad-Core
- Intel Core i7-860Rival
Lynnfield i7
- AMD Athlon II X4 645Rival
Budget Quad-Core
- AMD Phenom II X4 955 BEAlt
Unlocked quad-core at a competitive price with better multi-threaded throughput.
- Intel Core i7-870Alt
Eight threads on the same platform if budget allowed.
Intel Core i5-680
- Compare head-to-headIntel Core i5-750Rival
Quad-Core Desktop
- AMD Phenom II X4 965Rival
High-Frequency Quad-Core
- Intel Core i7-860Rival
Lynnfield i7
- AMD Phenom II X4 970Rival
Fastest Phenom II Quad
- Intel Core i7-870Rival
High-End Lynnfield
Our Verdict on Each
An interesting novelty for overclockers in 2010, but the unlocked multiplier on a dual-core Clarkdale offered little practical value even at launch.
Best for: Collectors or overclocking hobbyists interested in legacy hardware
Read the full reviewThe fastest Clarkdale ever made, but at $294 for two cores, it was a tough sell against the i5-750. Now entirely obsolete.
Best for: Completing a Clarkdale collection or keeping an existing system running
Read the full reviewFrequently Asked Questions
Which is faster for gaming, Intel Core i5-655K or Intel Core i5-680?
For gaming, the Intel Core i5-680 leads with a gaming performance score of 6/100 among Intel Core i5-655K and Intel Core i5-680.
Do Intel Core i5-655K and Intel Core i5-680 use the same socket?
Yes — all of these CPUs use the LGA 1156 socket, so they share compatible motherboards.
Which is faster in multi-core benchmarks?
The Intel Core i5-680 posts the highest multi-core benchmark score. Multi-core results: Intel Core i5-655K (4,380), Intel Core i5-680 (5,050). Benchmark figures are approximate and workload-dependent.