Intel Pentium III 1266S: specs and benchmarks

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Intel Pentium III 1266S
Intel Pentium III 1266S
  • Interface
  • Core clock speed
  • Max video memory
  • Memory type
  • Memory clock speed
  • Maximum resolution
Year of release 2001


Intel started Intel Pentium III 1266S sales on July 2001. Based on Tualatin architecture, this desktop processor is primarily aimed at home systems. It has 1 core and 1 thread, and is based on 130 nm manufacturing technology, with a maximum frequency of 1266 MHz and a locked multiplier.

Compatibility-wise, this is Intel Socket 370 processor with a TDP of 30 Watt and a maximum temperature of 69 °C.

We have no data on Pentium III 1266S benchmark results.

General info

Of Pentium III 1266S processor market type (desktop or notebook), architecture, sales start time and pricing.

Place in performance ratingnot rated
Market segmentDesktop processor
Architecture codenameTualatin
Release dateJuly 2001 (20 years ago)

Technical specs

Basic microprocessor parameters such as number of cores, number of threads, base frequency and turbo boost clock, lithography, cache size and multiplier lock state. These parameters can generally indicate CPU performance, but to be more precise you have to review its test results.

Physical cores1 (Single-Core)
Boost clock speed1.27 GHzof 5.3 (Core i9-10900KF)
L1 cache8 KBof 896 (Atom C3950)
L2 cache512 KBof 12288 (Core 2 Quad Q9550)
Chip lithography130 nmof 5 (Apple M1)
Die size80 mm2
Maximum case temperature (TCase)69 °Cof 105 (Core i7-5557U)
Number of transistors44 millionof 16000 (Apple M1)
64 bit support-
Windows 11 compatibility-
Unlocked multiplier-


Information on Pentium III 1266S compatibility with other computer components and devices: motherboard (look for socket type), power supply unit (look for power consumption) etc. Useful when planning a future computer configuration or upgrading an existing one. Note that power consumption of some processors can well exceed their nominal TDP, even without overclocking. Some can even double their declared thermals given that the motherboard allows to tune the CPU power parameters.

Number of CPUs in a configuration1of 8 (Opteron 842)
Thermal design power (TDP)30 Wattof 400 (Xeon Platinum 9282)

Benchmark performance

Single-core and multi-core benchmark results of Pentium III 1266S. Overall benchmark performance is measured in points in 0-100 range, higher is better.

  • Passmark

Passmark CPU Mark is a widespread benchmark, consisting of 8 different types of workload, including integer and floating point math, extended instructions, compression, encryption and physics calculation. There is also one separate single-threaded scenario measuring single-core performance.

Pentium III 1266S 309

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Intel Pentium III 1266S
Intel Pentium III 1266S

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