Steamroller (microarchitecture)

1. Kaveri A-series APU
   • Desktop budget and mainstream markets (FM2+): The Trinity / Richland APU line was replaced in January 2014 by the Kaveri APU line, as the third generation of A10, A8, A6 and A4 series for the desktop market. Top-of-the-line model in 2014 was the quad-core A10-7850K APU, with a 3.7 GHz core frequency and 4 MB L2 cache, incorporating a 720 MHz GPU with 512 stream processors and over 856 GFLOPS of total processing power.[13]
     In 2015 and 2016 new models with two to four enhanced Steamroller B cores were released as Kaveri-refresh / Godavari. A10-7890K, the new top-of-the-line model, features an increased core frequency of 4.1 GHz and an 866 MHz GPU.
   • Two or four CPU cores based on the Steamroller microarchitecture
   • Socket FM2+-only, Socket FM2 is not supported,[14] support for PCIe 3.0
   • DDR3 Dual-channel (2x64-bit) memory controller
   • AMD Heterogeneous System Architecture (HSA) 2.0
   • SIP blocks: Unified Video Decoder, Video Coding Engine, TrueAudio[15]
   • Three to eight Compute Units (CUs) based on the revised GCN 2nd gen microarchitecture;[16] 1 Compute Unit (CU) consists of 64 Unified Shader Processors : 4 Texture Mapping Units (TMUs) : 1 Render Output Unit (ROP)
   • AMD Eyefinity up to 4 monitors,[17] 4K Ultra HD support, DisplayPort 1.2 Support[18]
   • Select models support AMD Hybrid Graphics by using a Radeon R7 240 or R7 250 discrete graphics card.[19]
   • Integrated custom ARM Cortex-A5 co-processor[20] with TrustZone Security Extensions[21]
2. Berlin APU - canceled
   • Announced in 2013 by AMD[22] the Berlin APU were targeted at the enterprise and server markets featuring four Steamroller cores, up to 512 stream processors and support for ECC memory.

In November 2013 AMD confirmed it would not update the FX series in 2014, neither its Socket AM3+ version, nor will it receive a Steamroller version with a new socket.[23][24]

AMD however, released a Kaveri based FX-770K for desktop and FX-7600P for mobile which are basically APUs with their integrated graphics disabled similar to the Athlon X4 FM2+ line. Those APUs were released for OEMs only.

AMD's server roadmaps for 2014 showed:[25][26]

• Berlin APU - quad-core x86 Steamroller architecture (as described above) for 1 Processor (1P) compute and media clusters
• Berlin CPU - quad-core x86 Steamroller architecture for 1P web and enterprise services clusters
• Seattle CPU - 4/8 core AArch64 Cortex-A57 architecture (Opteron A1100) for 1P web and enterprise services clusters [27]
• Warsaw CPU - up to 16 core x86 Piledriver (2nd gen Bulldozer) architecture (Opteron 6338P and 6370P) for 2P/4P servers [28]

However, plans for Steamroller Opteron products were cancelled, likely due to the poor energy efficiency achieved in this generation of the Bulldozer architecture. Energy efficiency was greatly increased in the following generation, Excavator, which exceeded Jaguar in performance per watt, and approximately doubled performance/watt over Steamroller (for example 20.74 pt/W vs 10.85 pt/W when comparing similar mobile APUs using rough arbitrary metrics).[29][30]