You are missing the point. If an SSD - like some people speculate in this thread - is to act as a slow RAM pool for asset streaming, you need to bring latency down with a huge margin (modern SSDs are good enough to act like slow RAM from a pure specification point of view). Direct Storage is an attempt to address this but will not in its current iteration completely succeed with this due to CPU overhead (still a very large improvement over today's situation).
You're only basing this on assumptions but where are the numbers to back up this belief that latency is still such an issue, even with NVMe 2.1 and PCIe 5.0, even with SAM/BAR, even with improving NAND modules increasing not just bandwidths but also lowering latency, even with improving DRAM caches and FMCs...that the latency figures won't be "good enough"? Even considering improvements in file I/O systems for OSes like Windows 11 and Linux distros, you just seem to be plainly ignoring all of this.
CPU speeds are only getting faster, with better integration of caches at last-level hierarchies. All of these things drive down the latency cost, let alone standards that can layer on top of PCIe like CXL which bring even lower latency alongside other benefits when talking about CXL 2.0 and especially 3.0. There's little more preventing a decently spec'd consumer PC (let alone higher-end PC systems or enterprise server clusters) from utilizing SSDs as a slow RAM pool for asset streaming than there is for the PS5. It's not the miracle wunderkid of I/O far out ahead of the class that you've been telling yourself it is. That doesn't mean it's bad, not by any means. But it's not in its own league, so to speak, when taking a look at the wider market of today.
To achieve this, the GPU would need to be allowed to call a file on the SSD and directly read it into VRAM without CPU involvement. This is technologically possible on a PC but will not be allowed for multiple security reasons in Windows.
It already exists with things like GPUDirectStorage on Nvidia GPUs. Also there are other OSes besides Windows :/
So to paraphrase your text: Yes, yes, yes - Direct Storage is a CPU run driver to control traffic faster to the VRAM pool but will still suffer from a CPU tax in terms of latency due to that every I/O step still being 100% under CPU control. This is the EXACT same reason why you need VRAM on your graphics card on a PC. Yes - you have all that super fast RAM on your motherboard and a very fast PCIe bus but that RAM and bus is under CPU control that introduces very high levels of latency that necessities VRAM on your card so you can cut the CPU out of the core graphics I/O cycle.
Again, if the CPU in question has enough overhead, this "tax" means virtually nothing, and CPUs for the PC space alone are only getting better and better. Once you get into the enterprise, cloud etc. space, then it's literally a non-issue; implementations in those spaces can handle I/O throughput magnitudes higher than the consoles simply on spare CPU cores and threads.
Also again, you're forgetting about SAM/BAR, which was introduced not that long ago to help streamline addressing schemes between the CPU and GPU.
This fundamental bottle-neck is not in place for next-generation consoles.
The consoles have their own bottleneck of sorts: shared usage of the bus enforced by bus arbitration. That's part of what comes with current hUMA memory architectures. Standards like CXL and OMI especially bring hUMA benefits to nUMA memory architectures with equivalent (or in case of OMI, superior) low latency than conventional hUMA memory designs, but I'll be fair and admit those things are not in the consumer PC space (gaming or otherwise), so don't bare as much mention here.
And for those that think this is console warring against PC: I play more games on my high-end PC than my console. This is simply about technology and how to evolve the PC platform.
Except the PC is already evolving and has addressed quite a few of the things (or are in the process of addressing quite a few of the things) you still seem to think are keeping it in the stone ages compared to consoles. And actually, I think the taste of some exaggeration that can maybe be picked up from your insistence on this console I/O vs. PC I/O discussion is what's more the issue, at least with me.
Truthfully speaking consoles have never had any technological advantage over PC gaming for more than a year or two, so the idea of consumer PC I/O (for systems geared towards gaming) taking the lead over console implementations by this point isn't far-fetched. I remember you saying in the past you felt that consoles (specifically PS5) would stay ahead on this for the generation, or at least for a good few years. That isn't happening.
PC always leading the charge of bleeding edge technology. I remember getting my first ssd and installing Witcher 2 on it and couldn’t believe how fast it loaded.
ms just needs to hurry up with direct storage.
It's supposed to be coming this year, but probably in H2 at this rate.
