AMD Steamroller

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Steamroller is a microarchitecture designed by AMD for x86 processors with 64-bit expansion . It is the successor and further development of AMD Bulldozer and Piledriver. The successor to AMD Steamroller was the microarchitecture Excavator in 2015 .


AMD has mainly optimized the front end of Steamroller, which should have a significantly higher throughput, as well as the FPU. This is achieved with one command decoder per integer core, so that there should no longer be a bottleneck there. Further innovations:


The Steamroller CPU core architecture was launched in January 2014 as part of APUs with the code name Kaveri . These APUs are manufactured with a minimum structure size of 28 nm .

Due to another revision, APUs optimized for the integrated graphics and with further clock increases came onto the market in 2015. The top model A10-7890K, for example, has 400 MHz more base clock and 300 MHz more turbo clock on the CPU side than the A10-7850K. The revision, christened by AMD Kaveri-Refresh , also became known under the name Godavari .

Kaveri and Kaveri Refresh APUs are designed for the FM2 + socket and, according to the manufacturer's recommendations, should be combined on motherboards with the Fusion Controller Hubs (FCH) A88X, A78, A68H or A58.


The direct successor to Steamroller and the fourth generation of AMD's clustered integer core architecture is the Excavator architecture. Excavator supports new instructions like AVX2 , BMI2 and RdRand . In addition, DDR3 SDRAM - and DDR4 SDRAM memory controller on the same The integrated. The Excavator - CPU core design uses high-density libraries, which are more commonly used in GPUs to save energy and space and to work up to 30 percent more efficiently. Excavator cores are designed for heterogeneous system architecture in order to utilize the CPU and GPU, which is supposed to increase performance. Excavator modules are supposed to handle up to 30 percent more IPC than their steamroller predecessors.


The system-on-chips based on the CPU core architecture Excavator for use in desktop , mobile and embedded systems were given the code name Carrizo by AMD . Most of them are APU models, but chips with deactivated GPU are also provided for desktop computers . The APU was designed to be HSA-1.0 compatible. Corresponding APUs for mobile computers were first presented in June 2015. The new FP4 socket is intended for mobile devices and embedded systems . So far, models with one or two modules have been published. With the Athlon X4 845 , the first Carrizo model for desktop computers was released in February 2016 , the motherboard of which is equipped with the FM2 + socket .

APUs with the code name Bristol Ridge contain revised Excavator CPU cores ("Excavator Gen2"). These represent the final generation of AMD's implementation of the clustered integer core design. The APUs support the AM4 socket and DDR4 SDRAM.


At the beginning of 2017, AMD Zen replaced the clustered integer core architecture,which was originally introduced in 2011 with the Bulldozer CPU cores and has since been revised several times.

Individual evidence

  1. (slide 14-22)
  2. Kevin Carbotte: Don't Call It 'Godavari'; AMD Updates Kaveri APUs With DX12, FreeSync And VSR Support In: tom's HARDWARE , May 29, 2015.
  3. AMD: AMD A-Series Chipsets - FM2 + Platform
  4. AMD presents the sixth APU generation “Carrizo” for notebooks . Planet3DNow !. June 3, 2015. Accessed December 8, 2015.
  8. a b Mark Hachman: AMD reveals high-end 'Carrizo' APU, the first chip to fully embrace audacious HSA tech . PCWorld. November 21, 2014. Retrieved January 15, 2015.
  9. Hassan Mujtaba: AMD Opteron Roadmap Reveals Next Generation Toronto and Carrizo APU Details . WCCF Tech. December 26, 2013. Retrieved January 15, 2015.
  10. AMD: AMD Discloses Architecture Details of High-Performance, Energy-Efficient “Carrizo” System-on-Chip , press release from February 23, 2015.
  11. Sam Reynolds: New confirmed details on AMD's 2014 APU lineup, Kaveri delayed . October 31, 2013. Retrieved November 24, 2013.
  12. AMD updates product roadmap for 2014 and 2015 . August 26, 2013. Retrieved November 24, 2013.
  13. Related Excavator CPUs for socket BGA (FP4) .
  14. Marc Sauter: AMD publishes Carrizo for Socket FM2 + In: , February 2, 2016.
  17. ( Memento of the original from May 13, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot /
  18. Khalid Moammer: AMD's Next Gen x86 High Performance Core is Zen . WCCF Tech. September 9, 2014. Retrieved January 15, 2015.