DirectStorage arrives on PC to exploit the potential of NVMe SSDs

DirectStorage arrives on PC to exploit the potential of NVMe SSDs

With the arrival of DirectStorage on PC, developers will now be able to exploit the full potential of NVMe SSDs as they already do on console.

In fall 2020, Microsoft announced that its DirectStorage data transfer system would take the plunge from Xbox to PCs, giving them the ability to fully exploit the blazing transfer speeds enabled by modern NVMe SSDs. . It’s now the big day: from today, all games will be able to benefit from this system which should allow PCs to compete with consoles in terms of loading time.

Concretely, DirectStorage is a Software development kit, or SDK. In essence, this term refers to a set of computer tools intended for developers and which generally allow them to implement third-party functionalities in their program. The feature in question here is a radically different data transfer architecture that dramatically improves physical memory access speed.

Starting today, games can be deployed with DirectStorage. This public SDK launches a new era of fast loading and detailed worlds in PC games by allowing developers to fully utilize the speed of the latest storage systems”, can we read in the press release from Microsoft.

Turn the SATA page

This last term designates above all NVMe SSDs (for Nonvolatile Memory Express). This is a technology that offers very impressive speeds thanks to a major conceptual difference; unlike older SSDs that use the SATA bus, these use the PCIe bus directly.

This SATA bus is a major bottleneck; it drastically limits the overall performance of modern systems, much like a group of cyclists being forced to slow down to wait for a straggler on a children’s tricycle.

The NVMe bus, on the other hand, is significantly faster than the SATA bus. Where the latter is a small country road full of ruts, the latest PCIe standards are huge highways that allow immense amounts of data to spin at full speed.

From then on, the roles were reversed; whereas the SATA transfer bus used to be the drag of data transfer, the NVMe bus is so fast that it’s the rest of the system that has to upgrade. Because it’s one thing to be able to transfer that data at lightning speed; you also need to be able to extract and use them just as quickly.

A completely different approach…

This is an aspect on which manufacturers have worked a lot on the latest generation of consoles, which offer extremely fast loading times. But this type of technology is still awaited on consumer PCs, and it is to this lack that DirectStorage now responds.

When the system wants to transfer from an SSD (here NVMe), it starts by sending the data to the system’s random access memory (DRAM). The first step is to “unpack” this data, which is kept in compressed form on the SSD. Traditionally, the CPU takes care of this step; after having dissected this packet of data, it can then send it to the memory of the graphics card (VRAM) so that the latter can process it in turn.

The problem is that the RAM, as fast as it is, is too slow for modern games that require massive graphics processing power. The poor CPU therefore spends its time decompressing data to feed the graphics card, in addition to performing its many other tasks; you don’t need to be an engineer to understand that there is certainly room to optimize this architecture.

…and much better optimized

And this is precisely what DirectStorage allows you to do: here, we completely remove the CPU from the equation. Once the data has been transferred to the DRAM, it will be sent directly to the VRAM of the graphics card. It is the latter which will then take care of decompressing its data itself before processing it.

It’s a much less meandering and more optimized approach, since the data encounters fewer intermediaries and remains in a compressed state until the very end of the chain. This has many advantages, starting with speed.

This is because the GPU is much more capable than the CPU when it comes to decompressing data; in practice, this results in higher data rates. For a developer, this opens the door to creating ever denser and larger worlds while benefiting from reduced loading times.

In addition, it almost entirely frees the CPU of this thankless task which otherwise consumes a significant part of its resources. The icing on the cake: since this is a strictly software difference, this approach is not reserved for Windows 11 machines. PCs running Windows 10 also have access to it.

However, there is one major downside: DirectStorage must be specifically implemented by developers, which means that not all titles will benefit from it. The first to qualify will be Forspoken, which will serve as a technical demonstration for this new system. It will be presented at the next GDC, on March 23, before an expected release on October 11.

It is therefore not tomorrow that you will be able to exploit all the capacities of your brand new NVMe SSDs on all titles. But it’s the start of a generational transition that all PC gamers have been waiting for; Windows machines will soon be able to compete with specialized consoles on this very important criterion.

Leave a Comment

Your email address will not be published.