Portal: Prelude, a Portal mod made by Nicolas “Nyk018” Grevet, simply acquired the RTX remaster remedy 15 years after its preliminary launch. The mod now consists of full path tracing, DLSS 3, and Nvidia Reflex help. It additionally achieves a primary for PC gaming: it is the primary sport to help RTX IO, Nvidia’s implementation of a brand new commonplace aiming to hurry up texture loading occasions and scale back file sizes.
Portal: Prelude RTX is obtainable from at the moment over at Steam. Any RTX-branded GPU will seemingly be capable to run the sport—an RTX 2060 is the minimal requirement, although you’d possible require extra energy to actually kick path tracing into overdrive.
The brand new launch is not only a technical overhaul, both, there’s new voice performing and new check chambers to get indignant at included within the new and improved mod.
However the massive factor is that RTX IO help, as that is the primary sport (mod) to ever help the brand new GPU decompression expertise.
RTX IO is a method to shift the job of decompressing sport belongings, specifically excessive decision textures, from the CPU and as an alternative give it to the GPU. That is executed to scale back the time it takes to load textures in.
Take this cake from Portal: Prelude, proven in a check video from Nvidia. With out RTX IO, the cake’s textures are totally loaded in 3:46 seconds.
With RTX IO enabled, the cake is loaded in 1:01 seconds—greater than 3x quicker.
RTX IO is Nvidia’s approach of implementing GDeflate by itself GPUs. GDeflate is an open supply information compression scheme, and an vital step in higher utilising the {hardware} that almost all of us have already got in our PCs. However to grasp why that’s it’s a must to look into why at the moment’s CPU-based decompression is not a great answer.
Whereas taking part in a sport, the CPU spends quite a lot of cycles coping with compiling shaders, decompressing sport information, and initialising sport objects, as AMD outlines in a GDC presentation slide (PDF). The decompression duties really take up quite a lot of assets and system I/O bandwidth, and it is for that reason that shifting the busywork of decompression over to a GPU can really profit a consumer whereas gaming. With GPU decompression, a CPU is freer to work on different vital duties and you’ll keep away from conventional bottlenecks.
“When making use of conventional compression with decompression occurring on the CPU, it’s the CPU that turns into the general bottleneck, leading to decrease throughput than would in any other case be attainable with uncompressed streaming,” an Nvidia technical weblog says. “Not solely does it underutilize obtainable I/O assets of the system, but it surely additionally takes away CPU cycles from different duties needing CPU assets.”
For those who take away the decompression stage from the CPU, the sport information nonetheless goes by way of the CPU and system reminiscence, however the GPU can use its glut of cores to speed up the decompression course of.
For those who’re confused by how RTX IO suits in with all the opposite GPU decompression touting applied sciences, you are most likely not the one one. A whole lot of corporations have an element to play in implementing GDeflate and have their very own spin of it. Primarily, each Microsoft’s DirectX 12 and Khronos’ Vulkan APIs help GPU decompression—Microsoft by way of DirectStorage and Vulkan by way of Vulkan extensions.
Nvidia, Intel, and AMD will all help GPU decompression, GDeflate, on their very own graphics playing cards with driver help and related applied sciences. In Nvidia’s case, GeForce help is courtesy of what it calls RTX IO.
We’re seeing Nvidia pushing the expertise out to begin with beneath its personal banner because of the RTX Remix program, which provides it the flexibleness to work with builders intently on a mission like this. The primary main sport anticipated to help GPU decompression is Ratchet & Clank: Rift Aside, which can launch later this month with GPU decompression help courtesy of DirectStorage 1.2. That is extra prone to help all GPU {hardware} in due time.
Although you most likely want an NVMe SSD to actually benefit from these new storage applied sciences. It is not a requirement, even Ratchet & Clank will work on a standard exhausting drive, however the advantages will certainly be muted by a lot slower storage applied sciences. Little question it is a good time to improve to an SSD, if you have not already.