CPU Comparison
Intel Core i5-2500S vs Intel Core i5-661
A side-by-side comparison of specs, performance and value. The Intel Core i5-2500S is a power-optimized 65 W quad-core desktop processor from the Sandy Bridge generation, offering 2.7 GHz base and 3.7 GHz turbo speeds for small form factor PCs.
The Bottom Line
Overview & Launch
Specifications Compared
Performance Compared
Productivity
Handles legacy office workloads well, but sustained multi-core loads cause it to throttle below standard i5-2500 speeds.
Identical CPU performance to the i5-660, inadequate for modern productivity.
Gaming
Intel HD 2000 graphics prevent any meaningful modern gaming experience.
The 900MHz iGPU was slightly more capable than other Clarkdales but still cannot handle any modern 3D workload.
Virtualization
Good enterprise virtualization feature support, but limited by four total threads.
Two cores with Hyper-Threading offer minimal virtualization capability.
Efficiency
Excellent efficiency for 2011, drawing significantly less power at idle and light loads than 95 W parts.
87W TDP for a dual-core with basic integrated graphics represents very poor efficiency.
Specialized Performance
AI / ML
- No AI acceleration capabilities
- AVX support exists but lacks AVX2 for modern workloads
- Far too slow for practical AI tasks
- No AI capabilities
- Completely unsuitable for machine learning
Content Creation
Gaming
- Intel HD 2000 is a severe bottleneck for 3D rendering
- Can handle older 2D or very light 3D indie games
- Requires a discrete GPU for any acceptable gaming experience
- 900MHz iGPU was the fastest in Clarkdale but still far too slow for modern games
- Could handle very light 2010-era games at low resolution
- A discrete GPU was still necessary for any serious gaming
Industry Impact
Best CPU by Use Case
Target Audience
Strengths & Weaknesses
Pros
- Matches the 3.7 GHz turbo of the standard 95 W i5-2500
- 65 W TDP allows for much quieter, smaller cooling solutions
- Full enterprise feature set including TXT and VT-d
- Lower idle power consumption than standard desktop parts
- Reliable Sandy Bridge architecture
Cons
- Lower sustained multi-core clocks due to 65 W limit
- Intel HD 2000 graphics are very weak
- Locked multiplier
- No Hyper-Threading
- Obsolete platform with no upgrade path
Pros
- Fastest integrated graphics in the Clarkdale lineup
- Same capable dual-core CPU as the i5-660
- Good hardware video decode acceleration
- Interesting variant for collectors
Cons
- 87W TDP is high for a dual-core with basic iGPU
- GPU improvement was marginal in practice
- Same two-core limitation as all Clarkdale i5s
- No AVX instruction support
- Completely obsolete platform
Competitors & Alternatives
Intel Core i5-2500S
- AMD Phenom II X4 840TRival
Low Power Desktop
- AMD A8-3820Rival
Desktop APU
- Compare head-to-headIntel Core i5-2400SRival
Low Power Desktop
- AMD A6-3670Rival
Budget Desktop
- Compare head-to-headIntel Core i5-2500TRival
Ultra Low Power Desktop
If your SFF chassis can handle 95 W, the standard 2500 offers better sustained performance for less money.
Compare head-to-headIvy Bridge successor with better integrated graphics and slightly improved efficiency.
Compare head-to-head- Intel Core i7-2600SAlt
Adds Hyper-Threading (8 threads) for better multi-tasking within the same 65 W power envelope.
Intel Core i5-661
- AMD Athlon II X4 640Rival
Budget Quad-Core
- AMD Phenom II X2 565Rival
Dual-Core Desktop
- Compare head-to-headIntel Core i5-750Rival
Quad-Core Desktop
- AMD 880G Integrated PlatformRival
Integrated Graphics Platform
- NVIDIA GeForce 9400 GT + Pentium E6600Rival
Budget Discrete GPU Combo
Same CPU performance with 14W lower TDP for $10 less.
Compare head-to-head- AMD 880G PlatformAlt
Better integrated graphics performance from AMD's platform at lower cost.
Our Verdict on Each
A highly effective power-optimized Sandy Bridge chip that delivered excellent burst performance for its 65 W TDP, though entirely outclassed today.
Best for: Replacing a failed CPU in a proprietary Small Form Factor PC that strictly requires a 65 W or lower processor.
Read the full reviewThe faster 900MHz iGPU was a notable differentiator in 2010 but did not overcome the fundamental dual-core limitation. The 87W TDP was a significant penalty.
Best for: Running an existing i5-661 system for basic tasks
Read the full reviewFrequently Asked Questions
Which is better, Intel Core i5-2500S or Intel Core i5-661?
Based on our editorial ratings, the Intel Core i5-2500S comes out ahead with a score of 4.5/10. 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 i5-2500S or Intel Core i5-661?
For gaming, the Intel Core i5-2500S leads with a gaming performance score of 12/100 among Intel Core i5-2500S and Intel Core i5-661.
Which uses less power?
The Intel Core i5-2500S has the lowest rated TDP. Power draw across these chips: Intel Core i5-2500S (65 W), Intel Core i5-661 (87 W).
Do Intel Core i5-2500S and Intel Core i5-661 use the same socket?
No. They use different sockets (Intel Core i5-2500S: LGA 1155, Intel Core i5-661: LGA 1156), so each needs a compatible motherboard.
Which has more cores?
The Intel Core i5-2500S has the most cores. Core counts: Intel Core i5-2500S (4 cores), Intel Core i5-661 (2 cores).
Which is faster in multi-core benchmarks?
The Intel Core i5-661 posts the highest multi-core benchmark score. Multi-core results: Intel Core i5-2500S (3,800), Intel Core i5-661 (4,600). Benchmark figures are approximate and workload-dependent.