PCI express 3.0 vs PCI express 4.0

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So I noticed all the new Ryzen boards X570 support PCI express 4.0 while I still have PCI express 3.0 on my Intel Z370 Coffee Lake. I guess Comet lake will have PCI express 4.0 and maybe other chipsets from Intel

Do you think the upgrade will pay off at any time considering GPUs don't utilize all the power with PCI express 3.0 now?
 
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Watch the bus activity in GPU-Z while you're gaming. Outside of the initial loadup, the PCI bus will sit nearly idle the whole time. PCIe 4 basically will change that 99% idle time to 99.7% idle time. Not exactly a meaningful change.

Where we might see things change is with PCIe 5, which potentially offers sufficient speed and low latency to enable more widespread multi-GPU uses (like SLI/Crossfire, but better). I wouldn't hold my breath on this though.
 
In a system with 20 lanes or 1000 billion lanes like threadripper pci-e 4 doesn't change *much*. Where you will see benefits is in the future where severly limited chipsets have much more bandwidth with their fewer lanes.
 
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In a system with 20 lanes or 1000 billion lanes like threadripper pci-e 4 doesn't change *much*. Where you will see benefits is in the future where severly limited chipsets have much more bandwidth with their fewer lanes.

You make a very good point here. It is definitely nice in that it allows you to do the same stuff with fewer lanes. A 9900k, with its mere 16 lanes, would actually be able to support multiple GPUs + an NVMe SSD if it supported 4.0.

Aside from that though, being 2x the speed of 3.0 basically amounts to "same old shit but faster." I think that applies to a lot of tech generally. Once you hit 4x multipliers and above, new applications tend to become enabled by the improved tech.
 
Right now the advantage is with SSDs where PCI-E 4.0 SSDs show considerable improvements in performance, and we don't even have a "true" PCI-E 4.0 SSD controller yet. Future SSDs on PCI-E 4.0 will be even faster.
 
More lanes will eventually be very useful. I think more and more storage is gonna be moving to PCI-E as SATA phases out. I also expect some sort of external PCI-E connection to become popular in the next few years.

Immediately it's just future proofing, but because of how much I love my NVME storage I would love more PCI-E lanes now. Also if I want to add an Elgato capture card or similar.
I already have one NVME drive crippled by being on a PCI-E 2x instead of 4x.
 
In a system with 20 lanes or 1000 billion lanes like threadripper pci-e 4 doesn't change *much*. Where you will see benefits is in the future where severly limited chipsets have much more bandwidth with their fewer lanes.

Or you can run a dGPU off an x1 slot on a tiny motherboard. That will be awesome. Right now I think that for PCIe 3.0, anything below x4 for a GPU takes a severe performance hit.
 
I also expect some sort of external PCI-E connection to become popular in the next few years.

I think we’ll see some impressive gains in external connectivity options because of pcie4. You could already do a lot with thunderbolt 3 but every implementation of it I’ve seen (not sure if it’s TB3 design or just how everyone has implemented it) uses a pcie3 x4 lane for connectivity. Fine for lots of uses but if you wanted to do, say, an external ssd array, it would probably be limited by that x4 link.

if the next generation uses pcie 4 and a wider link it could be pretty huge. Like right now we’ve got external gpu enclosures with some USB ports and gigabit Ethernet, but I’m thinking of stuff like... multiple GPUs in a “compute box”, external ssd arrays with same as internally-connected performance, 10gbe networking, that sort of thing.

granted at a certain point it starts to look like having a whole computer on your desk, but I like the idea of having a modular setup as an option. You could upgrade processor, memory, all that stuff and still have render projects and all saved and ready to go, just a matter of connecting the box to the new system. Or vice versa, upgrade your Teslas without having to take your main box offline.

this is kind of what they said TB3 would be like, but near as I can tell so far it’s worked but hasn’t lived up to the hype (again, not sure if that’s a design limitation or implementation issue).
 
Right now the advantage is with SSDs where PCI-E 4.0 SSDs show considerable improvements in performance, and we don't even have a "true" PCI-E 4.0 SSD controller yet. Future SSDs on PCI-E 4.0 will be even faster.

The current crop of 4.0 SSDs are already benchmarking at roughly double the throughput of their 3.0 equivalents. That's pretty awesome in storage-heavy applications. As a practical matter, however, doubling that throughput doesn't really amount to much for most users - including gamers.

More lanes will eventually be very useful. I think more and more storage is gonna be moving to PCI-E as SATA phases out. I also expect some sort of external PCI-E connection to become popular in the next few years.

I would LOVE if this came to be. Unfortunately, it's been promised "any day now" for almost a decade and we still haven't seen much practical progress. I gave eGPUs the best shake I could and just ran into too many limitations in terms of both hardware and software support. The latter was limited by both the OS and the application software.

I think we’ll see some impressive gains in external connectivity options because of pcie4. You could already do a lot with thunderbolt 3 but every implementation of it I’ve seen (not sure if it’s TB3 design or just how everyone has implemented it) uses a pcie3 x4 lane for connectivity. Fine for lots of uses but if you wanted to do, say, an external ssd array, it would probably be limited by that x4 link.

TB3 is an incredible external connection bus, but at only 40Gbps, it is still quite limited compared to PCIe. That's why you're seeing it limited to only x4 links. With PCIe 4.0, you'd be seeing it with X2 links instead (but the same total throughput). I haven't kept up with rumors of TB4's capability, but I'd wager that release is still a long ways out.
 
Welcome to marketing and technology. Newer isn't always smarter especially financially.

In summary:
Your SSD will benefit will you notice a difference? Probably not.
"In the future" your new components will benefit from the additional benefit PCI-E 4.0. By that time you'll probably want to dump any board you buy now for something newer.

Honestly you could do a lot of blind hardware comparisons and most people wouldn't know the difference between a lower end chipset and a higher end chipset using the same cpu and video card. 99.9% of us can't tell the difference between cheap vs. expensive ram considering the what 1-3 FPS difference it makes.

Just something to consider. If you can get a great deal on a PCI-E 4.0 board go for it but it doesn't sound like you need to upgrade now unless you have money to burn. In that case send me that Z370 Coffee Lake I'd be happy to put it to good use. :)
 
There's some ramblings that PCIe 4 will be the one skipped. (everything will move to 5)

We'll see.
 
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