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Scorpio Engine
General Info
Designer	AMD, Microsoft
Manufacturer	TSMC
Model Number	Scorpio Engine
Market	Console
Introduction	June 11, 2017 (announced) November 7, 2017 (launched)
Shop	Amazon
General Specs
Frequency	2,300 MHz
Microarchitecture
ISA	x86-64 (x86)
Microarchitecture	Enhanced Jaguar, Polaris
Core Name	Enhanced Jaguar
Process	16 nm
Transistors	7,000,000,000
Technology	CMOS
Die	359 mm²
MCP	No
Word Size	64 bit
Cores	8
Threads	8
Max Memory	24 GiB
Multiprocessing
Max SMP	1-Way (Uniprocessor)
Packaging
Package	BGA-2409 (FC-OBGA)
Dimension	50 mm × 50 mm
Pitch	0.8 mm
Contacts	2409

Scorpio Engine is a 64-bit octa-core x86 SoC designed by AMD and Microsoft for their Xbox One X. The chip features eight Enhanced Jaguar cores operating at 2.3 GHz and a custom Arctic Islands-based GPU operating at 1.172 GHz. Fabricated on TSMC's 16FF+, this chip supports 12 (24 for Dev) GiB of 12-channel GDDR5-6800 memory.

Overview

Like the PlayStation 4 and the Xbox One, the Xbox One X is also powered by a chip based on AMD's architectures. The Scorpio Engine most important goal was achieving true 4K gaming performance according to John Sell, a Distinguished Engineer at Microsoft who presented the chip at Hot Chips 29. Fabricated on TSMC's 16 nm process, the chip contains 7 billion transistors on a 359 mm² die, similar in amount to Nvidia's GTX 1080 and almost the same size as the original Xbox One SoC (which was 363 mm² on a 28 nm process).

Like the original Xbox One SoC, the chip feature eight Jaguar cores. The cores have been lightly enhanced and operate at a higher frequency of 2.3 GHz, but are otherwise mostly identical. It's worth pointing out that AMD has not commercialized a 16 nm Jaguar processor outside of this chip.

Cache

Main article: Enhanced Jaguar § Cache

[Edit/Modify Cache Info]

Cache Organization Cache is a hardware component containing a relatively small and extremely fast memory designed to speed up the performance of a CPU by preparing ahead of time the data it needs to read from a relatively slower medium such as main memory. The organization and amount of cache can have a large impact on the performance, power consumption, die size, and consequently cost of the IC. Cache is specified by its size, number of sets, associativity, block size, sub-block size, and fetch and write-back policies. Note: All units are in kibibytes and mebibytes.

L1$ 512 KiB 524,288 B 0.5 MiB L1I$ 256 KiB 262,144 B 0.25 MiB 8x32 KiB 2-way set associative   L1D$ 256 KiB 262,144 B 0.25 MiB 8x32 KiB 8-way set associative write-back L2$ 4 MiB 4,096 KiB 4,194,304 B 0.00391 GiB     2x2 MiB 16-way set associative write-back

Memory controller

The memory architecture of the Scorpio Engine is very different from the previous generational chip. The entire memory subsystem was redesigned to address the major deficiencies in prior chips. In previous chip, Microsoft chose to go with 8 GiB of quad-channel DDR3 on-board operating at 2133 MT/s for a total system memory bandwidth of 63.58 GiB/s. That was fairly low by any standard; at the time the PS4 SoC had a peak memory bandwidth of 163.9 GiB/s. In an attempt to mitigate the lack of bandwidth, the chip incorporated 32 MiB of eSRAM with a bus of 1,024-bit in each direction for a total bandwidth of 190 GiB/s. While this reduced the cost of memory considerably, it increased the cost in terms of die area (which would be roughly 1.6B transistors). Additionally, this architecture also made the programming model more complicated to work with.

The Scorpio Engine made a 180-degree turn vs previous chip architecture-wise. The entire memory subsystem has been re-designed with GDDR5 and high bandwidth in mind. The previous 32 MiB of eSRAM has been eliminated. Instead, Scorpio has a maximum bandwidth of 304 GiB/s through a 384-bit wide DRAM interface with an effective transfer of 6800 MT/s. The bandwidth increase has effectively reached the level of a discrete graphics card and almost 1.5x the bandwidth of the PS4 Pro (which is 203 GiB/s).

Console systems will come with 12 x32 GDDR chips for a total of 12 GiB while the development system will come with x16 chips for a total capacity of 24 GiB. Scorpio has 12 DRAM controllers for each of the 12 channels. It's worth noting that in order to maintain backwards compatibility with the Xbox One software, the CPU and GPU accesses the memory separately. The exact details of how the CPU accesses the memory has not been detailed. As with the previous generation, a bidirectional bus sits between the memory controllers and the CPUs and GPU. The bus maintains coherency between the CPU cores and the GPU. For the GPU, each of the 12 channels is a 256-bit directional bus for a total bus width of 3,072-bit. The 12 channels allow the system to lower the granularity of memory accesses while the wide bus allows the system to take full advantage of the available bandwidth.

[Edit/Modify Memory Info]

	Integrated Memory Controller
	Max Type GDDR5-6800 Supports ECC No Max Mem 24 GiB Controllers 12 Channels 12 Width 384 bit Max Bandwidth 304 GiB/s 311,296 MiB/s 326.418 GB/s 326,417.514 MB/s 0.297 TiB/s 0.326 TB/s Bandwidth Single 25.33 GiB/s

Graphics

Further information: Arctic Islands microarchitecture

Hardware Accelerated Video Capabilities
Codec	Encode	Decode
MPEG-4 AVC (H.264)	4K @ 60 Hz	✘
HEVC (H.265)	4K @ 60 Hz	4K @ 60 Hz
VP9	4K @ 60 Hz	✘

Scorpio Engine feature 40 or 44 Compute Units (CUs) for the consumer console and dev kit respectively based on Arctic Islands (Similar to Polaris, Radeon RX 4xx). This is triple the amount over the original Xbox One SoC. The Compute Units operate at 1,172 MHz, each with 64 32-bit floating point multiply-accumulate units. At 1.172 GHz with 128 FLOP/cycle this chip can deliver 6.00064 TFLOPS raw peak performance - over four times previous chips (which were 1.3 and 1.4 TFLOPS). The dev kit can deliver a reported 6.6 TFLOPS with its four additional CUs. The performance of texture processing has also been increased to 187.5 G bilinear texels/second. Additionally, in each of the four shader arrays, there is one geometry engine for the purpose of doing fixed geometry processing, this is twice previous chip which is capable of 4.688 Giga primitives/second.

Similar to previous chips, Scorpio has 2 command processors (i.e., microcontrollers) that handle graphic and compute tasks however they are said to handle more parallel compute tasks than previous chip in order to increase performance. The number of ACEs (Asynchronous Compute Engine) on Scorpio has doubled to 4 in order to increase the parallelism possible. It's worth pointing out that since the Scorpio Engine is based on Arctic Islands, there are also two additional schedulers.

Scorpio Engine GPU
Unified shaders	2560 (64 × 40 CUs), (dev kit) 2816 (64 × 44 CUs)
ROPs	32
TMUs	160
Peak Performance	~6 TFLOPS (6,000,640,000,000 FLOPS), (dev kit) ~6.6 TFLOPS

RBs and Memory Subsystem

The render back-end has also been enhanced. The render back-end consist of eight Render Boxes (RB) color/depth engines, each with 256 KiB graphics L2 cache for a total of 2 MiB. Each pair of Render Boxes is wired to one Memory Controller Cluster (MCC). Each MMC consists of two dedicated memory controllers and two more that are shared between two pairs of MCCs. In total there are four clusters with each having two dedicated controllers and two more pair (4 controllers) of channels shared between a pair of MCCs for a total of 12 channels.

Display

Scorpio Engine supports DP 1.2a, HDMI 2.0b, HDCP 2.2, and two-stream MST. 4K, 64-bit, 3-surface resize and blending is supported.

Audio

8 custom processors.

Utilizing devices

The Scorpio Engine is used solely in the Xbox One X and its dev kit.

Die

• TSMC's 16 nm FF+ process
• 7,000,000,000 transistors
• 359 mm² die size

Yield & redundancy

In normal microprocessors such as typical CPUs and GPUs, when a core in the case of a CPU or a shader unit in the case of a GPU has a defect, it's common for manufacturers to disable those affected cores/shaders (typically in a symmetrical way) and sell those chips as lower end models. Since the Scorpio Engine is only found in the single-specification Xbox One X machine and its dev kit, binning is not as flexible. In an attempt to improve yield for the consumer models the Scorpio Engine actually incorporates 11 Compute Units (CUs) in each shader array for redundancy, 10 of them are operational while an 11th one is used as a spare. With 4 shader arrays, there are 4 spares and 40 enabled CUs. If one or a few compute units are faulty but the rest of the chip is fully functional, the spare CUs can be enabled to compensate for this. Fully unlocked Scorpio Engines are incorporated in the dev kits, though in lower volume than the consumer models.

Package

• Lidless ball grid array package with stiffener frame, 50 mm
  5 cm
  1.969 in
  
  × 50 mm
  5 cm
  1.969 in
  
  • 2409 balls, 0.8 mm
    0.0315 in
    
    minimum non-uniform pitch
  • 12 layer (5-2-5) organic substrate, flip chip die attachment

• 12 × 32 bit GDDR5 SDRAM interface
  • 850 MHz, 6800 MT/s, 326.4 GB/s total raw bandwidth
  • XBox consumer model: 1 × DRAM Down per channel, 256M×32 = 1 GiB

• 8-lane PCIe Gen 1, 2, 3 (8 GT/s) interface
  • Up to 5 ports configurable x4, x2, x1 with power-of-two alignment
  • x4 General Purpose Ports (x4 SSD M.2)
  • x4 Unified Media Interface (x2 South Bridge, x1 Ethernet, x1 spare)

• Display Port 0
  • DP 1.2a with 2-stream MST, HDMI 2.0b, HDCP 2.2
  • Resolution up to 4096 × 2160, 60 Hz

• Display Port 1
  • DP 1.2a input (lanes 0-1 used for HDMI passthrough via HDMI-DP converter in SB)

• Low speed interfaces:
  • S/PDIF output (TOSLINK connector)
  • GPIO
  • Sideband Interface (SB-TSI)
  • Serial VID Interface (SVI2)
  • JTAG

Package Diagram

All dimensions in millimeters.

Ball numbers

Pin Map

Pinout, top view. Click for a larger image and other views.

Spreadsheet

Pin Description

Signals with names ending in _N are active low.

Signal	Description
(A0-F0/A1-F1)_ADBI	DRAM Channel A-F, Subchannel 0-1 Address Bus Inversion
(A0-F0/A1-F1)_CAS_N	DRAM Column Address Strobe
(A0-F0/A1-F1)_CKE0	DRAM Clock Enable for Address/Command Bus
(A0-F0/A1-F1)_CLK0_P/N	DRAM Differential Clock for Address/Command Bus
(A0-F0/A1-F1)_CS0_N	DRAM Chip Select
(A0-F0/A1-F1)_DDBI_(0-3)	DRAM Data Bus Inversion, byte 0-3
(A0-F0/A1-F1)_DQ[31:0]	DRAM Data Bus
A-F_DRAM_RESET	DRAM Reset
(A0-F0/A1-F1)_EDC_(0-3)	DRAM Error Detection and Correction, Data Bus byte 0-3
(A0-F0/A1-F1)_MA_A[7:0]	DRAM Column/Row Address
(A0-F0/A1-F1)_MA_A12	DRAM Column/Row Address 12
A-F_MEM_CAL
A-F_MEM_VREFDQ	DRAM Input Reference for Data Bus
(A0-F0/A1-F1)_RAS_N	DRAM Row Address Strobe
(A0-F0/A1-F1)_WCK0/WCK1_P/N	DRAM Differential Forward Clock for Data Bus byte 0-1/2-3
(A0-F0/A1-F1)_WE_N	DRAM Write Enable
P_GPP_RX(0-3)_P/N	PCIe GPP Receive Data Differential Pairs
P_GPP_TX(0-3)_P/N	PCIe GPP Transmit Data Differential Pairs
P_UMI_RX(0-3)_P/N	PCIe UMI Receive Data Differential Pairs
P_UMI_TX(0-3)_P/N	PCIe UMI Transmit Data Differential Pairs
DP0_TX(0-3)_P/N	DisplayPort 0 Main Link Differential Transmitter Lane 0-3 or HDMI Channel 2, 1, 0, Clock
DP1_RX(0-3)_P/N	DisplayPort 1 Differential Receiver (HDMI passthrough)
DP0/DP1_AUX_P/N	DisplayPort 0-1 Auxiliary Channel or HDMI DDC Clock, Data
DP0/DP1_HPD	DisplayPort 0-1 Hot Plug Detect input
DP_AUX_ZVSS
SPDIF_OUT	S/PDIF Output (TOSLINK connector)
1P8V_GPIO(0-9)	GPIO
3P3V_GPIO(0-3)
AV_CLKIN_P/N
CLKIN_P/N
CLKIN_NB_P/N
DISP_CLKIN_P/N
X32K_X1/X2	32768 Hz Real Time Clock XTAL
RTCCLK	32768 Hz Real Time Clock
PSEN
PWROK	Power OK input; Indicates that all voltage planes and free-running clocks are within specification
RESET_N	Processor Reset
ALERT_N	SB-TSI Interrupt
SIC	Sideband Interface Clock (SB-TSI)
SID	Sideband Interface Data
THERMDA	Thermal Diode Anode
THERMDC	Thermal Diode Cathode
THERMTRIP_N	Temperature Trip Output
DBREQ_N	Debug Request input to JTAG controller
DBRDY	Debug Ready
TCK	JTAG Clock
TDI	JTAG Data Input
TDO	JTAG Data Output
TMS	JTAG Mode Select
TRST_N	JTAG Reset
BP_(0-3)	Break Point Indicator
ANALOGOUT
ANATSTIN_P/N
ANATSTOUT_P/N
ATE_TSTCLK_EN
BYPASSCLK_P/N
DIECRACKMON	Die edge crack monitoring
PLLTEST0
PLLTEST1
VDD_BURN_1/2
SVC	Serial VID Clock (SVI2)
SVD	Serial VID Data
SVT	Serial VID Telemetry
VDD_CORE	Core Power Supply
VDD_CORE_PROBE
VSS_CORE_PROBE
VDD_CORE_SENSE
VSS_CORE_SENSE
VDD_NB	North Bridge Power Supply
VDD_NB_SENSE
VSS_NB_SENSE
VDD_GFX	GPU Power Supply
VDD_GFX_PROBE
VSS_GFX_PROBE
VDD_GFX_SENSE
VSS_GFX_SENSE
VDD_MEM
VDD_MEM_SENSE
VSS_MEM_SENSE
VDD_MEMP
VDD_MEMP_PROBE
VSS_MEMP_PROBE
VDD_MEMP_SENSE
VDD_095	0.95 V Supply Voltage
VDD_095_SENSE
VSS_095_SENSE
VDD_18	1.8 V Supply Voltage
VDD_33	3.3 V Supply Voltage
VDD_FUSE
VDDBT_RTC_G	Integrated Real Time Clock battery power supply
VSS	Ground
A0_BYPASS
DLY_PSP_RESET
P_ZCAL_VDD_095
P_ZCAL_VSS
SPARE
TMON_CAL0
TMON_CAL1

References

• Sell, John. The Xbox One X Scorpio Engine (Presentation). Hot Chips 29. August 21, 2017
• Sell, John; O'Connor, Patrick. XBOX One Silicon (Presentation). Hot Chips 25. August 26, 2013
• Paternoster, Paul et al. XBOX SERIES X SoC – A Next Generation Gaming Console (Presentation, Slides). IEEE ISSCC 2021, 3.1. February 15, 2021