Quick Verdict
A minor clock speed bump over the i5-650 that did not address the fundamental two-core limitation. Obsolete for any modern use.
Overview
Launch
2010
Status
DiscontinuedGeneration
1st Gen (Nehalem successor)
Market
Desktop
The Intel Core i5-660 is a dual-core Clarkdale desktop processor clocked at 3.33GHz with Hyper-Threading and integrated Intel HD Graphics, launched in January 2010.
The Core i5-660 raised the base clock from 3.2GHz to 3.33GHz with a corresponding turbo boost increase to 3.
6GHz, but was otherwise identical to the i5-650 in every way. At $196 versus $176, the price premium was hard to justify for the small performance gain.
Specifications
Performance
Slightly faster than the i5-650 but still fundamentally inadequate for modern workloads.
Two cores with Hyper-Threading provide minimal virtualization capability.
Cannot run any modern game at acceptable frame rates.
73W for a dual-core processor is inefficient by modern standards.
- •Dual-core limitation makes most modern games unplayable
- •HD Graphics 733MHz cannot handle any 3D rendering
- •Was barely adequate for 2010-era gaming with a discrete GPU
- •No AI acceleration
- •Far too slow for any machine learning workload
Architecture
32nm
Process Node
Clarkdale
Codename
2C / 4T
Core Config
4 MB
L3 Cache
73 W
TDP
Architecture Overview
The i5-660 shares the Clarkdale dual-die package design with all LGA 1156 i5-600 series processors. A 32nm Westmere CPU die with two cores and 4MB L3 cache is paired with a 45nm die containing the memory controller and Intel HD Graphics. The 25x multiplier on a 133MHz BCLK yields the 3.33GHz base frequency.
CPU Design
Two Westmere cores with Hyper-Threading at 3.33GHz base, turbo boosting to 3.6GHz on a single active core. The 4MB L3 cache is shared between both cores.
Memory Subsystem
Dual-channel DDR3-1333 controlled by the integrated memory controller on the 45nm die, providing 21.3 GB/s bandwidth.
PCIe & I/O
16 PCIe 2.0 lanes directly from the CPU for a single graphics card.
Overclocking
Locked multiplier requires BCLK overclocking, which affects memory and PCIe frequencies simultaneously.
- 133MHz higher base clock
- 134MHz higher turbo boost
- Marginally better single-threaded performance
Key Highlights
- Slightly faster than i5-650
- Integrated graphics for basic display
- 32nm process was advanced for its time
- Hyper-Threading improves multitasking
- Only two cores
- Extremely outdated for any modern task
- Small performance gain over cheaper i5-650
- No AVX support
- Obsolete platform with no upgrade path
History
The Core i5-660 launched alongside the i5-650 on January 7, 2010, as part of Intel's initial Clarkdale desktop rollout. It occupied an awkward price point at $196, just $12 less than the quad-core i5-750 while offering half the physical cores. This pricing strategy confused many buyers and reviewers, who consistently recommended the Lynnfield i5-750 as the better value for anyone not specifically needing integrated graphics.
</br></br>The i5-660 found its niche primarily in OEM systems where the integrated graphics reduced build costs. Major manufacturers including Dell, HP, and Lenovo offered i5-660-based systems as mid-range options, targeting families and small businesses that needed more than a Pentium or Core i3 but did not require gaming capability. In this context, the processor made sense: it was fast enough for Office, web browsing, and media playback, and the integrated graphics eliminated the need for a discrete GPU.
</br></br>Technically, the i5-660 was notable for being among the first desktop processors to demonstrate that 32nm manufacturing could deliver meaningful frequency improvements. The 3.33GHz base clock and 3.
6GHz turbo were impressive for a dual-core in 2010, and the 32nm process kept power consumption reasonable. However, history has not been kind to Clarkdale; the dual-core design with weak integrated graphics represented neither the best computing value (that was Lynnfield) nor the best integrated graphics solution (that would come with Sandy Bridge).
Improvements over Previous Generation
- 133MHz higher base clock
- 134MHz higher turbo boost
- Marginally better single-threaded performance
Alternatives & Competitors
Should You Buy It?
Not Recommended for the right buyer
Maintaining an existing LGA 1156 Clarkdale system
Avoid if…
- Any new system build
- Running modern applications
- Gaming
- Productivity workloads
Use Cases
Interesting Facts
The i5-660 had two sSPEC codes (SLBLV and SLBTK), indicating manufacturing revisions.
At $196, it was only $20 more than the i5-650 but offered roughly 4% more performance.
The i5-661 launched at the exact same price but featured faster integrated graphics at 900MHz.
The 25x multiplier was one of the few Clarkdale SKUs with a non-even multiplier value relative to the 133MHz BCLK.
Clarkdale's dual-die packaging meant the CPU and GPU could theoretically be manufactured on different processes.
The 3.6GHz turbo boost was competitive with AMD's fastest dual-cores of the era.
Like all Clarkdale processors, the memory controller operated on the older 45nm die rather than the 32nm CPU die.
The i5-660 was frequently bundled with H55 motherboards in pre-built systems.
It was one of the last Intel desktop processors to lack AVX instruction support.
The 73W TDP included both the CPU die and the integrated graphics die power consumption.
People Also Ask
What is the difference between i5-660 and i5-650?
The i5-660 runs at 3.33GHz (turbo 3.6GHz) versus the i5-650's 3.2GHz (turbo 3.466GHz). Everything else is identical.
Can the i5-660 run Windows 11?
No. It lacks TPM 2.0 and modern instruction set support.
Does the i5-660 have integrated graphics?
Yes, Intel HD Graphics at 733MHz.
Is the i5-660 better than the i5-661?
They have the same CPU performance. The i5-661 has faster integrated graphics (900MHz vs 733MHz) but a higher 87W TDP.
What is the TDP of the i5-660?
73 watts.
Can the i5-660 be overclocked?
Only through BCLK adjustment since the multiplier is locked.
How much RAM can the i5-660 support?
Up to 16GB of DDR3-1333 in dual-channel configuration, depending on the motherboard.
What socket does the i5-660 use?
LGA 1156.
Was the i5-660 good for gaming in 2010?
With a discrete GPU, it could handle most 2010 games but showed limitations in titles optimized for quad-cores.
What is the turbo boost of the i5-660?
Up to 3.6GHz on a single core.
Frequently Asked Questions
What generation is the i5-660?
First generation Intel Core i5, based on the Clarkdale architecture.
Does the i5-660 support Hyper-Threading?
Yes, 2 cores with 4 threads.
What is the L3 cache size?
4MB shared.
What PCIe version does it support?
PCIe 2.0 with 16 lanes.
Does it support ECC memory?
No.
What chipsets are compatible?
Intel H55, H57, and P55.
What is the launch price?
$196.
How many transistors does the CPU die have?
382 million on the 32nm compute die.
What is the die size?
81mm² for the CPU die.
Does the i5-660 support VT-x?
Yes, hardware virtualization is supported.