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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  • cbrownx88 - Wednesday, May 22, 2013 - link

    Negative - they have an exclusive "launch on xbox FIRST" deal... No way EA would allow those franchises to be exclusive Reply
  • Friendly0Fire - Wednesday, May 22, 2013 - link

    Ghosts only has timed exclusivity on DLC. The game will see simultaneous release on all platforms. Reply
  • lmcd - Wednesday, May 22, 2013 - link

    What are you smoking? It's news but not surprising that EA is dumping the Wii U, but the PS4? That would be insane. And in fact, such a thing has not happened.

    Same with COD:G. AQll of the ones you have mentioned are cross-platform.
    Reply
  • blacks329 - Wednesday, May 22, 2013 - link

    Here is what is exclusive regarding EA Sports titles and CoD Ghosts.

    X1 will receive the Ultimate Teams feature exclusively. They haven't mentioned what that is. But the games themselves will release simultaneously on 360, PS3, X1, PS4 (assuming the last two arrive before the sports title is released).

    X1 will receive the CoD Ghosts DLC pack first, before it is released on PS4. Similarly to how it has been with every release of COD this gen for the past few years. CoD Ghosts will release simultaneously on 360, PS3, X1 and PS4.
    Reply
  • Inteli - Wednesday, May 22, 2013 - link

    I'm personally waiting to see someone strip Xbox OS from this and stick plain-old Windows on it. This might make a good HTPC without having to deal with any sort of specialized OS Reply
  • geniekid - Wednesday, May 22, 2013 - link

    That was one of the main draws of the PS3 until they removed the ability to run Linux on it. Reply
  • lmcd - Wednesday, May 22, 2013 - link

    Already has the Metro part of plain Windows. Reply
  • epobirs - Saturday, May 25, 2013 - link

    Why bother? You can build a mini-ITX HTPC using an AMD APU right now for less than the XO will likely cost at launch. I'm building a mini-ITX system right now that is thus far not breaking the bank. (To be fair, I got the Core i7-3770K for an unusually low price but I'd have settled for a low-power A10 model for about the same price and lower cost on the motherboard.) In fact, by taking it slow and gathering parts as deals come along, it has totaled remarkably little so far.

    I suspect Newegg has my phone bugged. Whenever I mention in a conversation not being able to find a good price on a particular needed item, I seem to get an email within hours with a sale on that item.
    Reply
  • Chad Boga - Wednesday, May 22, 2013 - link

    Why didn't Microsoft simply match the PS4's GPU capabilities? If they had, surely they then could have finished off Sony for good.

    Now Sony has a chance to once again become the premier gaming console.

    Microsoft has got so much wrong in the last decade and it looks like this is just a continuation of these stuff ups.
    Reply
  • tipoo - Wednesday, May 22, 2013 - link

    I think it's so that they can bundle Kinect at a competitive cost. Reply

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