The Xbox One: Hardware Analysis & Comparison to PlayStation 4
by Anand Lal Shimpi on May 22, 2013 8:00 AM ESTCPU & 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.
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bplewis24 - Wednesday, May 22, 2013 - link
"the Xbox One is MORE about consuming media THAN it is about playing games."FTFY
twotwotwo - Wednesday, May 22, 2013 - link
I hope it's just weak marketing, but what worries me is that the non-gaming extras don't sound all that new or interesting. A compelling, if unlikely, possibility would be to sell an upgrade that sticks Pro-compatible Windows 8 on the non-XBox side. MS is already selling a portable computer; why not sell a desktop/HTPC, too?SymphonyX7 - Wednesday, May 22, 2013 - link
If this was Top Gear, Jeremy Clarkson would be busy saying unpleasant things about the Xbox One right now."MORE SPEED and POWER!!!"
Oddly enough, I dreamt the night before the Xbox One launch that the new Xbox had 16 GB of DDR4 RAM and shader count equivalent to Tahiti @ 1 Ghz. I hoped that Microsoft with their virtually bottomless pockets could someone improve on the leaked Durango and Orbis specs which didn't bode too well for Durango. I mean, Sony doubled the RAM from 4 to 8 GB. And it's GDDR5 to boot!
Sigh. One can only dream -- no pun intended.
nafhan - Wednesday, May 22, 2013 - link
Don't think anyone has mentioned this yet, BUT another reason why MS can have slightly lower specs than the PS4: XBO and PS4 are close enough that cross platform games are likely going to target the weaker platform. Sony will be spending money on more powerful hardware that will only be utilized in first party/exclusive games. Side by side comparisons will (in most cases) show minimal - if any - differences.inherendo - Wednesday, May 22, 2013 - link
Can someone explain to me what bluray dsp is. Curious as to what Anand meant but googling shows no info.Kiste - Wednesday, May 22, 2013 - link
That alway-on Kinect thing is really creeping the hell out of me.This THING is always watching. Always. Unblinking. And it can see you in the dark. It can hear you. It can even measure your heart rate just by looking at you! It has a huge HAL9000 eye staring at you.
It even LOOKS evil.
I really don't want this thing... looking at me.
tipoo - Wednesday, May 22, 2013 - link
It's silicon. It's anonymized. I don't get what everyone has a problem with. It's not like this is letting the evil gub'ment spy on you.scottwilkins - Wednesday, May 22, 2013 - link
One thing I think that the article failed to point out was that even though there is a 33% difference in hardware on GPU, there is NOT a 33% different in performance. As the GPU grows in parts, the gains go up logarithmically, not linear like this article suggests. I'd say there is likely less than a 10% performance gain on the PS4 part. Yet it will use almost twice the power, be much more hotter requiring more loud cooling. Yuck! Add to that the performance of the Windows kernel for processing, something Sony could never be able to match, I'd bet that they are probably almost equal in the end.scottwilkins - Wednesday, May 22, 2013 - link
I believe I should have said "reverse logarithmically" meaning more parts equal less gain. I'm sure you guys get the point. Sony is betting on tech specs and market power rather than real processing power.tipoo - Wednesday, May 22, 2013 - link
In the absense of another bottleneck like memory bandwidth, within GPUs adding shader cores is actually a pretty good indicator of performance. And it's not just 12 vs 18 CUs, the PS4 also has double the ROPs and 172GB/s for its entire pool of memory.