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Draft:Crestmont (microarchitecture)

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Crestmont is the codename for Intel's fifth generation out of order Atom microarchitecture, and is the successor to Gracemont. It is used as the efficient-core and low power efficient-core microarchitecture in Intel's first generation Core Ultra processors (codenamed "Meteor Lake")[1], and Xeon 6 E-core processors (codenamed "Sierra Forest")[2].

Crestmont
General information
LaunchedNovember 4, 2023; 12 months ago (2023-11-04)[3]
Marketed byIntel
Designed byIntel
Common manufacturer
Performance
Max. CPU clock rate0.4 GHz to 3.8 GHz
Cache
L1 cache96 KB per core:
  • 64 KB instructions
  • 32 KB data
L2 cache2 or 4 MB per module
L3 cache3 MB per module (not present in Crestmont LP)[4]
Architecture and classification
Instruction setx86-64
Extensions
Physical specifications
Cores
  • 2 or 4 per module
Products, models, variants
Product code names
History
PredecessorGracemont
SuccessorSkymont

Design

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Crestmont contains the following enhancements over Gracemont:[5]

  • 6 wide rename and dispatch, compared to 5-wide in Gracemont
  • 6144 entry L2 Branch Target Buffer, compared to 5120 in Gracemont
  • Branch predictor can scan 128 bytes per cycle, compared to 32 bytes per cycle in Gracemont
  • Renamer can eliminate more µops by itself
  • Floating point divide latency reduced to 5 cycles, from 10 in Gracemont
  • Floating point scheduler sizes increased to a total of 60 entries, from 55 in Gracemont
  • L2 TLB size increased to 3072 entries with 6-way associativity, from 2048 entries with 4-way associativity

Technology

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  • Manufactured on Intel 4 (Meteor Lake compute tile)[1], Intel 3 (Sierra Forest compute tile)[6], or TSMC N6 (Meteor Lake SoC tile)[1]
  • 2 three-wide decoders in a cluster, each capable of fetching 32 bytes per cycle from the instruction cache
  • 6-wide rename/dispatch[7]
  • 256 entry reorder buffer[8]
  • 17 execution ports with distributed schedulers[5]
  • 32 kilobyte L1 data cache with eight-way associativity and 3 cycle latency[5]
  • 64 kilobyte L1 instruction cache with eight-way associativity[8]
  • 2-4 megabyte L2 cache with sixteen-way associativity and 17 cycles of latency shared between up to four cores[8]
  • Access to shared L3 cache with P-cores or other E-core modules on Meteor Lake and Sierra Forest

List of Crestmont processors

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See also

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References

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  1. ^ a b c Alcorn, Paul (September 20, 2023). "Intel Details Core Ultra 'Meteor Lake' Architecture, Launches December 14". Tom's Hardware. Archived from the original on June 8, 2024. Retrieved June 27, 2024.
  2. ^ Larabel, Michael (June 3, 2024). "Intel Launches Xeon 6700E "Sierra Forest" CPUs - Initially Up To 144 Cores". Phoronix. Archived from the original on June 4, 2024. Retrieved June 27, 2024.
  3. ^ Smith, Ryan (September 19, 2023). "The Intel Innovation 2023 Live Blog". AnandTech. Retrieved June 10, 2024.
  4. ^ Smith, Ryan (September 19, 2023). "The Intel Innovation 2023 Live Blog". AnandTech. Retrieved June 27, 2024.
  5. ^ a b c Lam, Chester (June 10, 2024). "Meteor Lake's E-Cores: Crestmont Makes Incremental Progress". Chips and Cheese. Archived from the original on May 28, 2024. Retrieved June 10, 2024.
  6. ^ Conway, Adam (26 September 2023). "Intel's process roadmap to 2025: Intel 7, 4, 3, 20A, and 18A explained". XDA-Developers. Archived from the original on March 28, 2024. Retrieved March 26, 2024.
  7. ^ "Meteor Lake's E-Cores: Crestmont Makes Incremental Progress". Chips and Cheese. 13 May 2024. Archived from the original on May 28, 2024. Retrieved June 10, 2024.
  8. ^ a b c Smith, Ryan (August 28, 2023). "Hot Chips 2023: Intel Details More on Granite Rapids and Sierra Forest Xeons". Anandtech. Archived from the original on May 11, 2024. Retrieved June 27, 2024.