Breaking Down Xbox one (Part 1: Hardware)

Hardware

The Wii U has been hacked (as far as revealing hardware), and Sony has been very open regarding the innards of the PlayStation 4; however, Microsoft has been very tight lipped regarding any finite details regarding their successor to the Xbox 360, Xbox One. All we really have from Microsoft is 8GB of DDR3 RAM 68 GB/s, 32MB eSRAM 200 GB/s, an 8-core custom CPU (still based on an AMD CPU), and a GPU that have been over-clocked to 1.31 TFLOPS. That seems like a lot, but it really tells us nothing about the technical abilities of what to expect from the Xbox One.

Let’s start with the easiest problem to solve, RAM and speeds. I guess you can technically say the Xbox One has more RAM than any other next-gen console since it has an extra 32MB of eSRAM, but going by sheer numbers 8.032GB of RAM isn’t going to improve a game by any kind of margin compared to purely 8GB of RAM. That being said the 32MB of eSRAM does hold a key benefit in its ability to process data faster than Microsoft’s 8GB of DDR3 at 68 GB/s and in this case even faster than Sony’s own GDDR5 RAM locked in at 176 GB/s. So with the 32MB of eSRAM and the speeds of Microsoft’s DDR3 RAM working together the Xbox One actually ends up with faster RAM than the PlayStation 4 clocked at 218 GB/s. At least that what it would be in theory, but as individuals involved in the world of computers, theory vs. practice often leaves wide gaps in performance loss especially when it comes to gaming / rendering. To put it simply 32MB of eSRAM isn’t nearly enough to push 8GB worth of data. In lower level RAM (such as the Wii U’s 2GB of DDR3 backed by 32MB of eDRAM, and the Xbox 360’s 10MB) eDRAM can literally double to RAM speeds at times which saves the Wii U RAM from being significantly outclassed by even the PS3’s RAM matching them for 25.6 GB/s, but only in a given moment. However, the Xbox One has eSRAM (reads and writes data faster than eDRAM) which also in theory could boost the Xbox One’s RAM speeds up 3x in a given moment, but the Xbox One is going to be hard pressed to see a tripling of RAM speeds consistently and safely (overheating is a serious issue), and it’s far more likely the RAM will be operating at a range between 50% - 80% increase or 102 - 122 GB/s (although Microsoft says it’s aiming for 130 - 140 GB/s).

The CPU is the Xbox One is another confusion piece to this puzzle. All rumors and theories point to the CPU being the same AMD Jaguar CPU found in the PlayStation 4. However, Microsoft has done their own “engineering” to the CPU to gain some benefits over the PlayStation 4 (most of which are due to the additional architecture found in the Xbox One like the various move engines), but the “engineering” simply consist of over-clocking the turbo cores traditionally found in the AMD Jaguar CPU to being with. Unfortunately the CPU isn’t the most important part of a gaming PC anymore it’s the GPU, and in a console that’s even more true. The CPU is to the GPU as the cloud is to the Xbox One, it’s there for support and running code, while the GPU handles most of the heavy lifting at least in consoles. That’s not to say that you can have just any CPU as a low core, low powered, and slow CPU will bottle neck even the most powerful GPU and allow weaker hardware to surpass it, but for these consoles that’s not the case and a near 10% clock boost isn’t going to make a huge difference. The only importance of the CPU boost is for Microsoft to obtain the label for the Xbox One as “the most powerful next-gen console CPU”. But what truly helps the Xbox One win the CPU war are its move engines, and a dedicated audio hardware. How much these help is unknown for now, but easing the workload off of the CPU is a plus in any case.

And here we go. There’s no real way to know what the GPU in the Xbox One is exactly. Microsoft claims that they’ve done “engineering” (7% over-clock) to their GPU to make a custom GPU; however, we do know the GPU is manufactured by AMD. However, Microsoft has confirmed a piece of key information, and that’s the Xbox One and PlayStation 4 GPU’s are both based on AMD’s Sea Island series. First let’s discuss what we know about the Xbox One’s GPU. The GPU is Sea Islands based and runs at 853 MHz, runs 768 threads, has 14 compute units but only 12 are useable, 16 ROPs (render output processors), and 1.31 TFLOPS. That’s a lot of information regarding the GPU, but based on those specifications (and the confirmation from Microsoft) the Xbox One GPU is nearly confirmed to be based on some kind of evolution to the AMD Radeon HD 7790 GPU (8870 / 8790 / 8870m) with an all around -20% reduction to the GPU (10% is reserved for apps and OS features, and another 10% was reserved for heating as with the PlayStation 4, more on that in the comments).

For those who don’t know the 7790 is a great mid-range GPU by today’s standards. It can play every current-gen games (based on PC specs.) at an average of around 40fps on medium - high settings in 1080p. Here are some examples of resolutions and framerates for games running on a PC with a HD 7790 (all games 1080p, High settings, 2x AA, unless noted otherwise):

Crysis 3: 1080p @ 50fps (Medium)
Metro 2033: 1080p @ 30fps
Hitman Absolution: 1080p @ 35fps
Sleeping Dogs: 1080p @ 45fps
Battlefield 3: 1080p @ 50fps
Tomb Raider: 1080p @ 55fps
Batman Arkham City: 1080p @ 60fps

As you can see the results are fairly solid, and more than capable of running the vast majority of current-gen games (again based on PC specs.) in 1080p with High settings at playable framerates. A drop down to medium-high settings would bring most current-gen games up to the ideal 1080p @ 60fps experience, for a slight hit on the graphics side. The alternative is to drop the resolution of games from native 1080p down to 1600 x 900 or 720p. As a standalone product the Xbox One is a more than capable console backed by a good amount of RAM with eSRAM to boost it’s performance, a solid CPU, and a solid GPU to push next-gen graphics.

Part 2
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