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PCIe 5.0 is nearly 4 years old and it's still virtually worthless in gaming PCs (pcgamer.com)
27 points by speckx 6 months ago | hide | past | favorite | 22 comments



Such a needlessly negative article. PCIe 5.0 is early, peripherals are scarce-to-non-existant, and existing rigs are not infinitely flexible. Otherwise, it all looks pretty good to me. Even buying one of those may prove worthwhile as new graphics cards and SSDs are released.


The point of this article is that the motherboard's distribution of relatively faster pcie5 lanes to devices and their physical slot sizing/numbers are currently inappropriate and limit the number of devices one can attach to a PC. This is not an invalid claim, or even limited to pcie 5.

All modern desktop motherboards have very limited expansion IO available compared to a similar class motherboard from a decade ago. Part of this is that all the IO protocols now are so fast you can't just have 8x nvme storage hook-ups (like you'd have 8x sata in the past) in the space of a modern board's controller chip(s) and the CPU. IO has grown faster than processing. And sharing pcie with GPUs makes this even worse.

The market has changed and desktop PCs assembled by humans with the expectation of adding new parts later is relatively smaller. And a smaller consideration is given to them versus the big (server/mobile) markets needs for pcie. This probably won't change but I think an article pointing it out as a bad thing for desktop computers is welcome. Maybe some high end mobo manufacturer (Asus?) can make a real non-server mobo with some actual physical IO (extra pcie 5 switch/bifurcation magic?) for the niche markets.


> All modern desktop motherboards have very limited expansion IO available compared to a similar class motherboard from a decade ago.

On what do you base this? The only thing I can think of is that a lot of unpopulated x1 PCIe slots got replaced with the much more useful m.2 slot.


I base it on using pcpartpicker to look for modern motherboards (last 2-3 chipset generations) with more than 6 sata ports or more than 3 nvme m.2 slots . Results are few and far between, and never together. And if they are when you look at the motherboard errata they often disable 1 of the m.2 nvme when the second GPU slot is populated, or an entire handful of the sata ports.


You can just buy an HP Z Workstation and you'll never fill up all those SSD slots. Plus SATA HBAs are $10/port so this seems like a weird hill upon which to die.


HP workstations are pretty locked down compared to a build it yourself desktop. Like, if some particular type of fan is not connected it won't boot, no way to disable it in BIOS/UEFI settings.

re: HBAs in general, yeah, I'll admit it's weird but I really don't like having to use external active controller cards for reading my storage. I just want my motherboard to do it to keep things simple.


I'll note that the bandwidth doubled from PCIe 4.0 to PCIe 5.0 (it's now 30GHz).

Dealing with that speed increase is causing a whole lot of problems for all the designers in the ecosystem. It's a bit of a nightmare, but people are for sure using it (in your laptops, in the data center).

We ended up adding some specific features/strategies to the autorouter we're building for to handle those speed. It was pretty hard to get right.


PCI-SIG is secretly run by a cabal for the benefit of the test and measurement equipment industry :-)


One type of foundational infrastructure got a few years ahead of its applications? Oh, the horror. The horror!


I think it’s a bit premature to conclude. It may be 4 years old but it’s not yet affordable and mainstream. AM5 is still at the start of what’s likely to be multiple generations



Has it occurred to them that gaming is not the only reason to have a computer?


You're literally commenting on an article from pcgamer.com.


The result is a very narrow definition of "virtually worthless". It indicates gaming might be too far into the diminishing returns curve so that a good gaming PC is no longer on the highest end of the desktop computing spectrum.


I mean they didn’t say virtually worthless they said “virtually worthless for gaming PCs”


The last three words of the title are a clear indication of the context of the discussion. It's perfectly legitimate to discuss tech as it applies to a specific (and popular) use.


More generally, games really don't tax computers very much. You can get a 400gbps network interface but it won't speed up your game. It does require a PCIe 5.0 x16 slot to hit that speed, though. It's the same for SSDs. Nobody is going to notice the difference between 10µs and 9µs 4K random read latency when launching Grand War United: Cyber 99, but it could substantially speed up the critical path of a database query. Games are not pushing the frontiers here.


> Games are not pushing the frontiers here.

Not anymore at least. Top-tier "GPUs" these days don't even have plugs for monitors. You won't see much of an improvement either by maxing out the memory - anything beyond 16GB will make very little change.

You might want to explore RAID-1 arrays to reduce that 9µs random read latency to 4.5µs or less (with more SSDs), but there is little benefit in transferring 8K UHD content faster than the monitor's frame rate allows one to watch it. I no longer see storage like that in the wild (as such things get abstracted away in cloud platforms) but I still remember RAID-1 "readzillas" and RAID-0 "writezillas" with a dozen or more fast disks (we used spinning metal when I last saw them). These are specially useful for back-ups, as they can ingest a truckload of data and spit them to tape at the maximum speed of the tape (avoiding a lot of wear and tear).


> For a computer to support PCIe 5.0, it needs one of two things, though preferably both.

So whats the second thing? It's never mentioned AFAICT. Assuming they meant in addition to PCIe host controllers on your CPU die (though could be in a south bridge or whatever) you need a PCIe 5.0 device?

The rest seems to complain about higher power consumption and heat. This is data center shit anyway so power and cooling aren't big issues there. Given enough time these issues will be fixed once consumer vendors starts caring enough to fix it. Or not. Who cares.


You mean we aren't doing realtime raytracing yet? Sad.


Wait, the only GPU supporting PCIe 5.0 is the NVIDIA H100 and it doesn't have RT-cores IIRC. Right?


Whew, now I don't need to feel bad that the pre-built gaming rig I bought last week only has PCIe 4.0 (Intel B660 chipset)




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