Brains vs. Brawn

A closer look at The Microchips and Muscle of XBox One and PS4

Platforms: PS4 and XBox One

Release Dates: November 15, 2013 (PS4) and November 22, 2013 (XB1)

By Malefico

So, both of the new consoles have arrived. Some of our resident writers have already snatched up PS4 and written about their first impressions and posted some game reviews. But I’m a hardware nerd, so I wanted to do some research and come up with some solid information on the APUs that drive the two newest entertainment boxes.

As has been amply reported elsewhere, both of the devices use modified AMD APU configurations, and superficially, they are quite similar. But each manufacturer has taken the basic design and tweaked it to their needs. Let’s go a little deeper into what makes these new consoles tick.

Chip Design

First, these two boxes use powerful processors. Sure, each of their processing cores is running at less than 2GHz, but with eight of them available per device, it really doesn’t matter. Since they are dedicated devices with their own OS, software developers are able to tailor applications to spread out processing tasks and make the most of the CPUs. The fact that both machines integrate a speedy set of Radeon graphics cores makes them well-suited to their intended tasks. The generic diagram below shows the basic structure of an APU. Know that the two consoles sport two banks of four CPU cores each, with attendant cache structures and system interfaces. I’ll include more detailed pics of each chip later in the article.

The CPU cores themselves closely resemble elements you would find in a laptop or tablet. Each next-gen console packs two groups of four cores onto the die. Individually, as noted above the cores are not very fast, but that pays dividends in a hardware application like this. Small, relatively slow cores are thrifty with power and generate less heat than those found in desktop computers. When you are running an 8-core chip, that matters. And, in these devices where space and therefore airflow are at a premium, every little bit counts. Sometimes, the two factors don’t go hand in hand. For instance, the Xbox One uses less power than PS4, but runs substantially hotter, 15-20 degrees hotter under load. Count on more frequent failures in the MS device than Sony’s offering.

I’m sure there are subtle differences in core structure, but these details are more suited for computer scientists than me.

The Paths Diverge

It’s clear that Microsoft put more emphasis on the raw computing power available to X Box One.

To start with, they tweaked the clock speed on their cores to 1.76GHz, slightly faster than Sony’s 1.6GHz units.

Then, MS added an extra 32MB of SRAM to their CPU design topping out at 47MB. Compared to Sony’s 15MB, this results in a significant data transfer advantage for Xbox. Simply put, Static Random Access Memory stores data differently than DRAM (Dynamic RAM, the kind found elsewhere in computing devices). Where DRAM has to be connected to a memory controller, which not only feeds and retrieves data but also refreshes the data about 1000 times per second, SRAM keeps data intact until the system calls for it without the need to refresh. It’s the kind of memory normally used to store data in a CPU’s cache levels. Very, very fast.

The presence of an extra quantity of SRAM on the X Box One brain means it will tend to process logical and numeric data more quickly than PS4.

It also means the MS chip will probably be a bit more flexible than Sony’s in line with Microsoft’s goal of making the XB1 into an all-around entertainment device. So it’s clear MS is counting on rapid data transfer to keep up with modern games. The strengths of the PS4 lie elsewhere, as we’ll see.

By comparison, Sony chose a more conservative CPU arrangement in order to shoehorn a substantially more powerful GPU onto the die.

Where the Xbox One features 12 active GPU cores, the PS4 has 18. In reality, each manufacturer chose to deactivate two cores, meaning they actually have 16 and 20 respectively. As a comparison, since both are Radeon units, the Xbox One utilizes a structure similar to Bonaire (HD 7700 series) while PS4 uses Pitcairn (HD 7800 series) technology. Isolating graphics execution, the difference in GPU performance is substantial, with PS4 gaining a 50% advantage in theoretical graphics chops. Because of the other variables involved, real-world realization will be much closer.

However, expect Sony to maintain a healthy lead in the graphics race. Images displayed on PS4 will be just a bit nicer than those on the new XBox. If you consider the environment, though, that won’t matter as much as it does on PC. In the living room, you’re typically sitting 8-10 feet away from the TV, while PC users are normally 2-3 feet from their monitors. Given the disparity in distance, the average person will notice differences on a PC whereas from the relatively more remote vantage point, they just won’t be as meaningful to users of the new consoles. Still, early comparisons of games like Battlefield 4 show the brutal truth. XBox One runs this game at 720p, the PS4 at 900. While neither offers true HD, the PS4 is that much closer. Incidentally, the difference in resolution points to the PS4’s 50% performance advantage in GPU power.

Let’s talk about system memory.

Both systems use a memory bus totaling 256 bits.

Microsoft went with fast DDR3 to feed their game beast. With 8GB running at 2133MHz, the system memory in XBox is respectable to say the least. But Sony went with 8GB of extremely fast DDR5 memory running at 5500MHz.

This is the kind of memory used in better-quality contemporary video cards. Although this looks like a no-brainer for Sony, like many specs the reality isn’t that clear-cut.

Latency is a term used to describe the lag in the number of RAM clock cycles between the request for a specific set of data and the time it actually leaves RAM. DDR3 running at 2133MHz has latency ranging from 11-14, while DDR5 varies from 18-20.

Another thing to remember about RAM is that it can be tailored to meet specific computing needs. Generally speaking, DDR3, the current standard for system memory does a better job of transferring data in serial fashion, one set after another, while DDR5, used in video cards does a better job dealing with graphics demands that entail simpler requests, but the need to deliver them in parallel, that is more than one at a time. Since the two memory types both use the same essential architecture, the difference is in how the memory bus handles data more than the memory itself. It also demonstrates why the two devices can use different memory types to come up with similar performance.

Again we see that the XBox will probably be the more well-rounded performer, but will most likely not measure up to PS4 where games are concerned.

We can also see clearly that where MS is banking on data transfer, Sony is using raw bandwidth to get things done.

Finally there is the issue of software and how it will be developed. This situation is also affected by the hardware. Microsoft has hinted that XB1 developers will be able to fine tune games at the hardware level. While this sounds good in theory and will no doubt help decrease the performance gap between the two machines, the question is will developers take the time to do this grunt work? Machine level coding is difficult and time-consuming and while XBox exclusive developers will probably use this feature, the great likelihood is that cross-platform ports will not make use of it.

The two companies have been clear about their goals. Xbox One aims to be a one-stop entertainment shop, while PS4 caters more to gamers. Seen in that light, both boxes have achieved their aims. With Microsoft’s stronger network, less specific hardware and the fact that Xbox One runs two operating systems, I can see them handily beating Sony when it comes to the ability to deliver diverse content.

For gaming though I stand by my early predictions. PS4 will bring Xbox to heel when it comes to video games.

Considering the trend to unify the entertainment experience, Microsoft may well sell more units than Sony, but XB1 will never outshine PS4 as a hard-core gaming device.

Written by Nerd Bacon