Now that the Playstation 4 has been released we have a good understanding of what lies inside the machine. In this article we’re going to be taking an overall look at the PS4’s internals and doing an analysis of all that lies beneath the black plastic shell. This article links to a lot of other articles we’ve covered if you want to learn much more about a subject – but this article will give you a good brief overview of the Playstation 4’s hardware.
CPU – AMD Jaguar X86-64 8 Core processor.
The PS4’s main CPU is AMD’s Jaguar Processor, each of the two modules holds four CPU cores, capable of one hardware thread each. The exact clock speed of the AMD Jaguar for the PS4 hasn’t been learned yet, but there are reports that it runs between 1.6 and 1.8GHZ. The Jaguar is a low power CPU, built to draw low power and provide high levels of performance in the device. Unlike Sony’s Playstation 3, it is an X86-64 CPU – meaning that it is a CISC instruction set (Complex Instruction Set Computer). This means that the device is easier to program, and more functions are available (such as memory operations) as instructions directly on the processor, rather than needing to code them specifically. The PS4’s CPU is also Out-of-Order execution, and due to advanced branch predictions, will waste much less time waiting for instructions when they ‘surprise’ the CPU – unlike the PS3’s Cell. The Jaguar also has 2MB of level 2 cache per module (4MB total), this is shared between the 4 cores.
The Playstation 4’s jaguar is not as powerful as a traditional desktop but still packs a good punch. It’s worth noting that 6 of the cores are believed to be available for games, while another 2 are reserved for the operating system. This has been shown in for example the Killzone Post-Mortem. The idea behind the next generation is to “go wide” – in other words, to split the jobs onto all of the cores available. For more details see the below image, and check out the Killzone Post-Mortem linked earlier.
GPU – AMD Radeon GCN
The Playstation 4 actually features 20 Compute Units using the GCN (Graphic Core Next) architecture, but there are two disabled due to yields. Each CU (Compute Unit) contains 64 shaders each – this means that you’re looking at 1152 total. The maths for this are simple enough – 64 * 18 = 1152. They are ‘clocked’ at 800MHZ, which puts out 1.84TFLOPS of peak performance. Each shader handles 2 instructions per clock (which is the same for all GPU’s using GCN – including the XBox One and desktop GPU’s). In addition, there are 32 ROPS in the machine, which are responsible for final rendering of the scene and applying certain effects such as Anti-Aliasing. The system features a complex GPGPU (General Purpose compute on Graphics Processing Unit) setup, with a total of 64 compute queues. For a detailed overview of the Compute structure and how similar it is to AMD’s next generation Volcanic Island R9-290 series cards, click here. The basic premise is to make it easy for the PS4 to queue a compute command, and then when there are free GPU cycles available (during a time in rendering where there is less stress on the GPU), it can run that compute command. This can be used for anything from AI, Physics and many other purposes. The PS4’s GPU also has a technology known as volatile bit. This technology allows a piece of code to be tagged with a bit of data, and then deleted or changed on the fly. This is a vast area of improvement from the traditional workings of GPU’s. It’s also worthy to note that AMD took many of the ideas of the PS4 – such as the beefed up compute structure and implemented it into their next gen video cards.
As for performance, the PS4’s GPU certainly isn’t as powerful as a high end PC desktop (many of which are capable of over 5TFLOPS – such as AMD’s own Radeon R9-290X), but is still very powerful. The GPU’s shader libraries are also very similar to AMD’s new upcoming API technology – Mantle (article). Mantle is a low level language which is capable of much better access to the GPU. In theory, this will allow much better PC ports and better cross compatibility – although it will need PC games developers to really adopt the mantle technology. Mantle certainly has advantages over DX11 for example, such as being able to process over 100,000 draw calls in a single frame.
Diagram of the R9-290X GPU – Notice the Compute Queues Similar to PS4’s GPU
PS4’s APU
The Playstation 4’s APU is comprised of the AMD Jaguar CPU and the GPU as described above. These are placed on the same package in an effort to reduce size and use APU computing (wiki link). The PS4 uses a custom chip, which Sony created alongside AMD. It is known as CXD90026G SoC (System on Chip) and measures 19.0 x 18.3 mm (348 sq mm) in size.
Memory – 8GB GDDR5 176GB/s bandwidth
The PS4’s main memory is using Samsung’s K4G41325FC – providing a refresh rate of 16K/32ms per 4GB. The RAM is clocked at 5500MHZ (effective, actual is 1375MHZ) on a 256-bit memory bus. This provides 176GB/s memory bandwidth (peak – games developers have said the PS4’s actual bandwidth is around 172GB/s). The memory is split into 16 chips, each 512MB. The memory isn’t that much higher latency compared to DDR3, which is a myth that continues to float about the internet – see article on analysis. GDDR5 memory is typically used in PC’s for their graphics card, and is lightning fast. Modern PC GPU’s feature higher bandwidth, but this isn’t shared for the GPU. The PS4’s Memory bandwidth is shared on the GPU / CPU using a system known as HUMA (article). This allows data to be read by the CPU and GPU and not needed to be copied from one memory location to another.
Think of HUMA memory as one large container which both the CPU and GPU have full access. Although I’d advise to read the previously linked article, the basic premise is that rather than needing to copy from one meory location to the other, with HUMA the PS4 has full access to everything. For example, if the CPU needs to access a piece of data in location A it can do so, and then not need to copy that piece of data to location B for the GPU to then process, then the GPU move the data back to A for the CPU to process. This is very different from the Xbox 360 – which despite have Unified Memory Access, the memory was divided. So for example, if a games developer wanted to allocate 200 MB of memory for graphics, the remainder for system they could. But, with HUMA this taken to the next step.
Not all of the PS4’s memory is available for games – and uses a technology known as flexible memory. See the below video for more info.
Playstation 4 Sound Chip
The sound chip inside the Playstation 4 is based on the same custom DSP design found in the next generation radeon cards – Article here. Its main purpose is to offload work from the CPU and to allow high quality surround sound, along with effects which take a lot of CPU cycles such as reverb, echo and real time positional sound. AMD’s TrueAudio API is very similar to that of the Playstation 4, which no doubt is a benefit to not only Sony but to AMD too. AMD have been trying to push the audio from their Radeon GPU’s, and with this technology inside the PS4 it’ll likely entice games developers to start exploring it.
Secondary Processor
The Playstation 4’s secondary processor isn’t fully understood yet. We know that it will help with various network tasks, although there are theories that this second chip will also help to background download and encode footage. Article here. The secondary chip also comes with 2Gb (256MB) of DDR3 memory, which runs at 2133MHZ.
Serieal Flash Memory
The PS4 uses Macronix MX25L25635FMI 256Mb Serial Flash Memory, although currently just like the secondary processor we don’t know exactly what its uses are. There are theories that it is being used to capture gameplay with the share button, for example video clips or to capture screen shots but this is currently not confirmed. There are an additional two Macronix MX25L1006E CMOS Serial Flash Memory on the system too.
Ethernet Controller
The PS4’s Ethernet Controller is similar to the PS3’s and uses the Marvell Alaska 88EC060-NN82 chipset.
USB3
As you’d expect, the PS3 does indeed feature the latest USB standard – USB 3, the PS4’s chip is a Genesys Logic GL3520 USB 3.0 Hub Controller. USB 3’s transfer rate is 10GB/s.
PS4’s Hard Disk
The Playstation 4’s 500GB hard drive (with reports of about 400GB being usable) is a 2.5 inch, 5400 RPM, 500 GB, SATA II from HGST. You can of course replace the PS4’s hard drive with one of your choosing, including a Sata 3 drive (which is a backwardly compatible standard). You may also put in a Solid State Drive (SSD), Hybrid Drive or a traditional HDD.
Optical Drive – Blu-Ray
The Playstation 4, just like its predecessor the PS3 uses a Blu-Ray drive for optical media. We’re not quite at the fully digital age yet. Sony have opted for a much faster drive this time around, 3x faster the PS3’s. It is capable of reading 400GB discs (that’s 16 layers).
Custom Clock Chip
IDT 6V41265NLG is a name you might not be familar with, but we believe it is what is responsible for ‘talking’ with the main APU and the PS4’s secondary processor.
