Excavator (microarchitecture)


AMD Excavator Family 15h is a microarchitecture developed by AMD to succeed Steamroller Family 15h for use in AMD APU processors and normal CPUs. On October 12, 2011, AMD revealed Excavator to be the code name for the fourth-generation Bulldozer-derived core.
The Excavator-based APU for mainstream applications is called Carrizo and was released in 2015.
The Carrizo APU is designed to be HSA 1.0 compliant.
An Excavator-based APU and CPU variant named Toronto for server and enterprise markets was also produced.
Excavator was the final revision of the "Bulldozer" family, with two new microarchitectures replacing Excavator a year later.
Excavator was succeeded by the x86-64 Zen architecture in early 2017.

Architecture

Excavator added hardware support for new instructions such as AVX2, BMI2 and RDRAND.
Excavator is designed using High Density Libraries normally used for GPUs to reduce electric energy consumption and die size, delivering a 30 percent increase in efficient energy use. Excavator can process up to 15% more instructions per clock compared to AMD's previous core Steamroller.

Features and ASICs

Processors

APU lines

There are three APU lines announced or released:
  1. Budget and mainstream markets : Carrizo APU
  2. * The Carrizo mobile APUs were launched in 2015 based on Excavator x86 cores and featuring Heterogeneous System Architecture for integrated task sharing between CPUs and GPUs, which allows a GPU to perform compute functions, which is claimed provide greater performance increases than shrinking the feature size alone.
  3. *Carrizo desktop APUs were launched in 2018. The mainsream product has 4 Excavator cores and a GPU based on GCN1.2 architecture. Also, an entry-level APU with 2 Excavator cores is also launched.
  4. Budget and mainstream markets : Bristol Ridge, and Stoney Ridge, APUs
  5. * Bristol Ridge APUs utilize socket AM4 and DDR4 RAM
  6. * Bristol Ridge APUs have up to 4 Excavator CPU cores and up to 8 3rd generation GCN GPU cores
  7. * Up to a 20% CPU performance increase over Carrizo
  8. * TDP of 15W to 65W, 15–35W for mobile
  9. Enterprise and server markets: Toronto APU
  10. * The Toronto APU for server and enterprise markets featured four x86 Excavator CPU core modules and Volcanic Islands integrated GPU core.
  11. * The Excavator cores has a greater advantage with IPC than Steamroller. The improvement is 4–15%.
  12. * Support for HSA/hUMA, DDR3/DDR4, PCIe 3.0, GCN 1.2
  13. * The Toronto APU was available in BGA and SoC variants. The SoC variant had the southbridge on the same die as the APU to save space and power and to optimize workloads.
  14. * A complete system with a Toronto APU would have a maximum power usage of 70 W.

    CPU Desktop lines

There are no plans for Steamroller or Excavator architectures on high-end desktop platforms.
Excavator CPU for Desktop announced on 2nd Feb 2016, named Athlon X4 845.In 2017, three more desktop CPUs were launched. They come in Socket AM4, with a TDP of 65W. In fact, they are APUs with their graphics cores disabled.
CPU modelFrequency CoresTDP SocketL1D cacheL2 cachePCI Express 3.0Relative IPCLocked
Athlon X4 845 3.5 465Socket FM2+ 4*32KB2*1MBX81.0Yes
Athlon X4 940 3.2 465Socket AM4 4*32KB2*1MBX161.1No
Athlon X4 950 3.5 465Socket AM4 4*32KB2*1MBX161.1No
Athlon X4 970 3.8 465Socket AM4 4*32KB2*1MBX161.1No

Server lines

The AMD Opteron roadmaps for 2015 show the Excavator-based Toronto APU and Toronto CPU intended for 1 Processor cluster applications: