System Architecture

Alex Bensch, Pete SevichCMPE 550, Spring 2014

Outline

• PS4 high level overview and history• PS4 Main Board• Jaguar Microarchitecture• APU/GPU specifics• Conclusion

History of the PlayStation

PlayStation (1994)PS2/PSOne (2000)PS3 (2007)PS4 (2013)

PS4 System Overview

PS4 Features

• “Play as you download”• Remote play support w/ PS Vita• Hardware supported streaming

– Integrated streaming software in overlay– Live or previous gameplay

• DualShock 4 controller support

DualShock 4

• 6 axis IMU (3+3 DOF)• Lightbar• MicroUSB extension port• LED Touchpad display• Bluetooth 2.1 communication• 3.7V LIPO battery

– 1000 mAh capacity

PS4 Hardware

• 8 CPU Cores @ 1.6GHz (x86-64)• 8GB GDDR5 Memory, 176GB/s• Radeon 7870-Based GPU• Blu-Ray/DVD Drive• 500GB HDD• 802.11 b/g/n, Gigabit Ethernet• USB 3.0, Bluetooth 2.1

Main PCB

Accelerated Processing Unit (APU)

• Combines CPU and GPU modules in SoC• Advantages

– Compact– Cost effective– Low power

• Disadvantages– Lower spec ceiling– Shared memory between GPU and CPU could limit

performance potential• PS4 uses a custom APU w/ Jaguar modules

Jaguar Implementations• Netbooks, tablets• Mini‐PCs, notebooks• Microservers• Thin clients• XB1 and PS4 

Jaguar General Information

• Mid 2013• 28nm lithography • Low‐power (6‐25W TDP*)• Big improvements over Bobcat • Allows APU implementations• 2 or 4 cores, up to 2.05GHz*• Split 64kB L1, up to 2MB shared L2• DDR3/DDR3L 1066‐1600* + ECC*Based on current implementations

PS4 APU Details

• Two quad-core Jaguar CPU modules– 1.6GHz clock – Each core has split 64kB L1 cache– Shared 2MB L2 cache (16 way associative)

• Modified Radeon 7870 GPU– 800MHz clock– 18 compute units (“cores”)– 1152 shader cores– 1.84 TFLOPS shader performance

Jaguar Pipeline

Pipeline Highlights

• Two issue, six dispatch– Six instructions fetched at once– Two decoded per cycle

• Appears to use Tomasulo– Out of order scheduling– Multiple issue

Comparison to Bobcat

• 15% increased OOS window– 56 entries for Bobcat– 64 entries for Jaguar

• Expanded FP op bus and vector units– 64-bit for Bobcat– 128-bit for Jaguar

• Additional iDec and RegRead stage in pipeline

Performance

• FP Ops– Multiply

• Single precision - 2 cycles• Double precision - 4 cycles

– 5 for X87 and only every third cycle– Division - 14-22 cycles– Square root - 16 - 35 cycles

• Some reciprocal square root ops - 2 cycles

Summary

• PS history• PS4 basics and hardware• Jaguar Microarchitecture• PS4 APU/GPU specifics

Questions?

Differences with Xbox One

• 1.75GHz CPU• DDR3 RAM• 47MB eSRAM*• 853MHz GPU• 12/14 CUs• 768 shader cores• 1.23 TFLOPS