xbox-one-ps4-generation-ahead-of-pcs-analysis

Rajat Taneja, Executive Vice President and Chief Technology Officer at Electronic Arts made huge waves in the tech industry when he recently said to Linkedin

“Both the Xbox One and PlayStation 4 have adopted electronics and an integrated systems-on-a -chip (soc) architecture that unleashes magnitudes more compute and graphics power than the current generation of consoles. These architectures are a generation ahead of the highest end PC on the market and their unique design of the hardware, the underlying operating system and the live service layer create one of the most compelling platforms to reimagine game mechanics”

Meanwhile, Mark Rein from Epic Games called this statement “bullshit” in a recent twitter comment.

Truthfully, I’m with Mark Rein on this one – Rajat has simply not provided any basis for his argument, only extremely broad terms. The APU design of the Playstation 4 and Xbox One does have advantages, mostly mirrored in the fact that both systems have slower CPU’s than a modern gaming PCs, and secondly due to parallel computing becoming more important.

mark-rein-twitter-comment

The CPU and GPU can speak to one another, with the GPU taking over certain tasks it is better at, while leaving the CPU to handle other tasks. For example – Physics need to be calculated, and the GPU can step up. General game code? The CPU’s is your man. There is no doubt that this form of computing (which AMD dubs fusion) will become increasingly important. But, the PS4’s and Xbox One’s raw output is far lower than that of a modern gaming PC. Let’s do a little exploring…

The AMD Jaguar in both systems uses two modules of 4 cores, giving 8 low power cores available, each handling 1 thread each. In terms of raw performance, the CPU’s are far lower in performance than a high end desktop CPU – and bare in mind, that they should be. The Jaguar is a low power device, targeted for laptops, note books, tablets and the like.

The GPU core of the PS4 (which is the fastest out of the two next generation consoles, 1.84TFLOPS compared to 1.24TFLOPS for the Xbox One) is certainly a step above the Xbox 360 and PS3. But to say that it is a generation ahead of the highest end PC’s is… ludicrous. The GPU itself is using the same GCN technology of the AMD Radeon 7000 series, which is available for desktops. The Radeon 7970 is far faster than that of the PS4’s GPU. The Radeon 7970 has 3.79GFLOPS of computing power, and that card is readily available to any gamers for PC.

The Geforce Titan, along with several other cards are more powerful than the Radeon 7970, and this is also not taking into account either CrossFire, or SLI. In this process, 2 or even 3 GPU’s can be “linked together” to render games at even faster frame rates. Many times, screen resolutions of 1920×1080 (1080P) can be handled easily by these cards, indeed – some cards even can run triple monitor solutions.

https://www.youtube.com/watch?v=k6CrjRbOdAs

The memory bandwidth issue is a lot more complicated.

PC’s have two main memory pools, main system RAM and Video RAM. Main system RAM is likely to be DDR3 – the exact same type of memory in the Xbox One. Memory bandwidth here can vary depending upon speed of the DDR3 ram installed on the machine. You could install the exact same type of memory as the Xbox One uses (DDR3 2133MHZ RAM) if you so wish. Because this RAM is not feeding the GPU, bandwidth is being used for the CPU and other system functions only. Right now, we know for sure that modern desktop CPU’s are getting closer to saturating the bandwidth of DDR3, but we’re not quite there yet.

Video memory is the second memory pool – these cards have typically GDDR5 RAM (the same as found in the PS4). The Radeon 7970 has 264GB/s memory bandwidth, compared to 176GB/s of the PS4. This memory bandwidth is purely for the GPU. Now, this is where it starts to get sticky.

The PS4 design does have a HUGE benefit – the 8GB of GDDR5 memory can be divided up as needed, between graphics, sound, AI, and whatever else. The Video RAM on a GPU is fixed, usually between 1,5GB and 3GB. Right now, we’re rare using more than 2GB (at 1080P) – but that situation could change in time. It could likely mean in a few years time that we’ll be seeing GPU’s which far larger amounts of RAM than we’re currently using. Especially given the memory usage of Killzone Shadow Fall on the Playstation 4. In Killzone Shadow Fall, the developers loaded HUGE amounts of textures and other image assets into memory that mean 3GB of the Playstation 4’s RAM is being used, purely on graphics. It’s worth noting that some of these are on things such as Streaming Pool. The PCIE bus CAN swap data between the main system memory on the Graphic Cards RAM – but it is slower. For now, 2GB of RAM is more than enough. In tests being done, unless you’re gaming at very high resolutions (usually three monitors, which are resolutions of up to 5760x1080P – far higher than the standard 1920x1080P).

This situation will likely change in the future – but for now, we’re fine as is.

So – what about the PCIE interface. PCI-E 2 and PCI-E 3 are the current standards. Virtually any modern gaming PC will come equipped with PCI-E 2, and the newer motherboards will support the 3.0 standards. Right now, PCI-E 2 bandwidth isn’t being saturated. This means that there is little to no performance difference between a PCIE 2 or 3 slot. There are a few exceptions – a very high end GPU – especially once in cross fire or SLI starts to see a few percent of difference between the cards – but because most of the textures and other image assets are stored locally on the GPU’s memory, the PCI-E bus is only really used to tell the card what to do and basic communications. Of course, there are examples when this isn’t true – loading new areas will mean the bus is being loaded with data instead – but in those instances, gameplay might pause (say between levels).

So does that mean that the PS4 and XBox One have no benefits to PC architecture? No – that’s not true. For the start, the APU design combined with easy to access high amount of memory bandwidth does afford the developers flexibility. The problem is, that the flexibility is not really going to matter for PC’s – because they can overcome much of this with pure brute force. The PS4 and XBox One designs are more elegant however. If AMD have their way, the APU fusion design will become the normal in desktops too. If that’s the case, it’ll integrate with a high end GPU to better display graphics.

I must admit – I’m very impressed with the PS4 and XBox One – they will both be fantastic machines. Their design may be a glimpse into the PC’s future – but then, it’s hard to really know for sure if AMD’s vision for desktops will really pay off. What we can agree on is that the power of both the XBox One and PS4 are only going to be a good thing for PC – especially since the games will be so much easier to port due to the X86-64 CPU.