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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bji - Wednesday, May 22, 2013 - link
I like the 8 year or longer console cycle. It means that I can focus on enjoying games more than upgrading every couple of years to the latest and greatest that isn't really any more fun to play, just has more eye candy.Hrel - Wednesday, May 22, 2013 - link
"We already have the Windows kernel running on phones, tablets, PCs and the Xbox, now we just need the Xbox OS across all platforms as well." That, 100 infinity BAGILLION times that!I'd actually like to see Nintendo release a console in time for X-mas 2014 with comparable hardware performance. Just because otherwise I don't see how that company will survive and I really don't want Nintendo to go away. I don't know if that's within their realm of possibility but they need to do something because the wiiU is pretty terrible.
tipoo - Wednesday, May 22, 2013 - link
But they won't, as laughable as Wii U sales are that would still anger however many bought that, likely their core base. They'll survive anyways, see their cash reserves, plus any platform Mario and Zelda et al come to will be fine. Nintendo survives on first party, always has.tipoo - Wednesday, May 22, 2013 - link
That said, yes I would have preffered if they just kept motionplus controls and the cost of the tablet controller instead went to an APU.skatendo - Friday, May 24, 2013 - link
Seriously? Have you even tried the GamePad for an extended period of time? The thing is incredible and very useful. Also, the Wii U CPU/GPU is very customized and tailored for gaming. It's smart Nintendo didn't release tech specs because most everybody wouldn't understand how it would perform in real time. Custom silicon is a magnificent thing. Heck look at the 4-core CPU and 12-core GPU for the Tegra 3 and pit that against a paltry looking dual core CPU/GPU Apple A5 and you wouldn't have any competition right? (on paper at least) And who would have thought that the A5 with A FOURTH THE CORES and much slower clockspeed outperformed about twice the game performance the "superior" Tegra 3.marc1000 - Wednesday, May 22, 2013 - link
a great thing MS could do is find a way to put Windows Phone 8 inside of Nvidia Shield - and then have the option to stream your game from the Xbox One to to Shield.That would be awesome, family could be watching TV on the living room and you could have high-quality gaming anywhere - event if it would not be possible to play on the console AND shield at the same time, of course.
Streaming games from X1 to Shield (full control scheme) or any WP8 phone/tablet (simpler games) would be that killer-app that MS needs so badly to boost it's phone business.
nforce4max - Wednesday, May 22, 2013 - link
Interesting read and excited that GCN is being used but the cpu side of things I have to wonder how it will actually perform. Bobcat was fairly weak (think of a Pentium 4) and was terrible starved of memory bandwidth but the worst was that the L2 cache only worked at half the core clock. If the Jaguar cores still have the same sluggish L2 cache then even 8 of them is going to be painful but I suppose devs are going to offload what they can onto the gpu (openCL).As for the 32mb on die memory as stated in the article it all comes down to how it is used. If used for the frame buffer it will limit resolution but make for a huge fps boost as the rop and tmu are bandwidth hogs gpu wise but leave the rest for the cpu and shader. The cpu being weak as it is won't need much provided the gpu doesn't hog to much of the bandwidth. If used as a cache it will make up for the weak L2 cache and provide a unified pool for all 8 cores, if software only then we might have to wait to find out what for.
Overall this is good news for the PC, no more games like GTA4 :D
Arsynic - Wednesday, May 22, 2013 - link
Listening to Sony PR and Sony fanboys you'd think PS4 had every advantage under the sun and will retail for $400.MooseMuffin - Wednesday, May 22, 2013 - link
Nice article Anand. Rare to get level-headed analysis at the start of a console cycle.highend - Wednesday, May 22, 2013 - link
Amiga CDTV in 1990 looked better than XBOX One, see yourself: www.amigahistory.co.uk/cdtv.jpg Also M$ copied from Commodore looks & design