CPU & GPU Hardware Analyzed

Although Microsoft did its best to minimize AMD’s role in all of this, the Xbox One features a semi-custom 28nm APU designed with AMD. If this sounds familiar it’s because the strategy is very similar to what Sony employed for the PS4’s silicon.

The phrase semi-custom comes from the fact that AMD is leveraging much of its already developed IP for the SoC. On the CPU front we have two Jaguar compute units, each one with four independent processor cores and a shared 2MB L2 cache. The combination of the two give the Xbox One its 8-core CPU. This is the same basic layout of the PS4‘s SoC.

If you’re not familiar with it, Jaguar is the follow-on to AMD’s Bobcat core - think of it as AMD’s answer to the Intel Atom. Jaguar is a 2-issue OoO architecture, but with roughly 20% higher IPC than Bobcat thanks to a number of tweaks. In ARM terms we’re talking about something that’s faster than a Cortex A15. I expect Jaguar to be close but likely fall behind Intel’s Silvermont, at least at the highest shipping frequencies. Jaguar is the foundation of AMD’s Kabini and Temash APUs, where it will ship first. I’ll have a deeper architectural look at Jaguar later this week. Update: It's live!

Inside the Xbox One, courtesy Wired

There’s no word on clock speed, but Jaguar at 28nm is good for up to 2GHz depending on thermal headroom. Current rumors point to both the PS4 and Xbox One running their Jaguar cores at 1.6GHz, which sounds about right. In terms of TDP, on the CPU side you’re likely looking at 30W with all cores fully loaded.

The move away from PowerPC to 64-bit x86 cores means the One breaks backwards compatibility with all Xbox 360 titles. Microsoft won’t be pursuing any sort of a backwards compatibility strategy, although if a game developer wanted to it could port an older title to the new console. Interestingly enough, the first Xbox was also an x86 design - from a hardware/ISA standpoint the new Xbox One is backwards compatible with its grandfather, although Microsoft would have to enable that as a feature in software - something that’s quite unlikely.

Microsoft Xbox One vs. Sony PlayStation 4 Spec comparison
  Xbox 360 Xbox One PlayStation 4
CPU Cores/Threads 3/6 8/8 8/8
CPU Frequency 3.2GHz 1.6GHz (est) 1.6GHz (est)
CPU µArch IBM PowerPC AMD Jaguar AMD Jaguar
Shared L2 Cache 1MB 2 x 2MB 2 x 2MB
GPU Cores   768 1152
Peak Shader Throughput 0.24 TFLOPS 1.23 TFLOPS 1.84 TFLOPS
Embedded Memory 10MB eDRAM 32MB eSRAM -
Embedded Memory Bandwidth 32GB/s 102GB/s -
System Memory 512MB 1400MHz GDDR3 8GB 2133MHz DDR3 8GB 5500MHz GDDR5
System Memory Bus 128-bits 256-bits 256-bits
System Memory Bandwidth 22.4 GB/s 68.3 GB/s 176.0 GB/s
Manufacturing Process   28nm 28nm

On the graphics side it’s once again obvious that Microsoft and Sony are shopping at the same store as the Xbox One’s SoC integrates an AMD GCN based GPU. Here’s where things start to get a bit controversial. Sony opted for an 18 Compute Unit GCN configuration, totaling 1152 shader processors/cores/ALUs. Microsoft went for a far smaller configuration: 768 (12 CUs).

Microsoft can’t make up the difference in clock speed alone (AMD’s GCN seems to top out around 1GHz on 28nm), and based on current leaks it looks like both MS and Sony are running their GPUs at the same 800MHz clock. The result is a 33% reduction in compute power, from 1.84 TFLOPs in the PS4 to 1.23 TFLOPs in the Xbox One. We’re still talking about over 5x the peak theoretical shader performance of the Xbox 360, likely even more given increases in efficiency thanks to AMD’s scalar GCN architecture (MS quotes up to 8x better GPU performance) - but there’s no escaping the fact that Microsoft has given the Xbox One less GPU hardware than Sony gave the PlayStation 4. Note that unlike the Xbox 360 vs. PS3 era, Sony's hardware advantage here won't need any clever developer work to extract - the architectures are near identical, Sony just has more resources available to use.

Remember all of my talk earlier about a slight pivot in strategy? Microsoft seems to believe that throwing as much power as possible at the next Xbox wasn’t the key to success and its silicon choices reflect that.

Introduction Memory Subsystem
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  • plcn - Wednesday, May 22, 2013 - link

    there are a lot more ipads than xboxes out there... msft wants the surface to have its place there, and well, that will probably make them more money than simply winning this generation's 'console war' - makes some sense. wasn't messaged like that at all by the company, but gotta appreciate it's potential merit nonetheless Reply
  • tipoo - Wednesday, May 22, 2013 - link

    Meh. If they kill the box and make tablets and mobile their gaming focus, that gives the iPad and Android an ample opportunity to become their prime competitors, and the iPad already has a lot of headway on mobile gaming. Reply
  • Jaybus - Wednesday, May 22, 2013 - link

    I don't think we can connect 2 or more controllers plus LCD TV to our smartphones just yet. And neither a smartphone nor a tablet can play high end games, certainly not at anything close to reasonable frame rates. Those who think a smartphone is going to replace consoles, PCs, and NASA supercomputers in the next 8 years all live in fantasy land. Reply
  • Gigaplex - Thursday, May 23, 2013 - link

    Sure we can. There's a fair few phones with HDMI connectors, and it wouldn't take much in the way of software tweaks to pair multiple bluetooth controllers (assuming it's not already supported). Reply
  • Dedhed - Wednesday, June 05, 2013 - link

    Actually I have a note 2 and attached to the smartdock and a couple of powered usb hubs i can connect 4 controllers to it and watch it on my 28 monitor or 55 led panel, hook up my external drives and play my bluray movies as well as surfing and netflix and the rest of it while listening to my stereo bluetooth headset. Convergence is happening already. Take off your blinders and look around! Reply
  • RollingCamel - Thursday, May 23, 2013 - link

    They wouldn't. First you have SmartGlass which makes the smartphones and tablets into controller peripherals as a 1st step of integration.
    Then these peripherals would evolve more into an accessory gaming controller paired with the Xbox system.
    After that the Xbox system grows from the living room into tablets and smartphones where games are played cross-platform. Every device does it job and can't replace the other. If ppl argue that we may hookup the phone to the TV instead of the console, it would be possible but imagine getting a phone mid game.
    This may increase MS sales if they can improve ground they built now. Every product they made has excellent potential and just needs to be smoothed out...hopefully.
    Sony has already spoken about integrating different devices into same ecosystem via Android. I don't think Apple can compete with it unless they use their tv box as a console too.
    Reply
  • jaydee - Wednesday, May 22, 2013 - link

    What's with all these "One" monikers?

    Since PS4 and XBO are all x86 architecture, here's hoping EA Sports will starting porting its games (notably Madden) to PC again.
    Reply
  • nathanddrews - Wednesday, May 22, 2013 - link

    I believe that Microsoft secured exclusive rights to all EA Sports titles for the XO, at least FIFA, Madden, NBA Live and UFC so far. Then there's COD:G which is exclusive as well. Whether these are temporal exclusives, DLC exclusives, or something else, I don't know. Reply
  • plcn - Wednesday, May 22, 2013 - link

    sorry to say, but they're not exclusive at all. they might have some exclusive features ('ignite'?) or early DLC, but the games are confirmed for PS4, too. Reply
  • THizzle7XU - Wednesday, May 22, 2013 - link

    Ignite is only the name of their next gen game engine. Reply

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