4k gaming & VR at 120 fps requires PCIe 4.0

JoseJones

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Jun 6, 2012
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I just read that if we want ... "4K video at 120Hz (or 240Hz) on a PC will require PCIe 4.0"

How true is that comment? I'm hearing that with NVMe fast storage and VR, we will need PCIe 4.0 if we want 4k gaming and VR at 120 fps or 144 fps or whatever especially with 21:9 ultra-wide.

Also, is PCIe 4.0 coming out in 2017 or not? I'm hearing that there's been another delay until 2018?

PCIe 4.0 Heads to Fab, 5.0 to Lab

PCIe 4.0 Will Arrive in 2017

Who are we suppose to trust - it seems everything is far too often just flat wrong?

What's the latest news on PCIe 4.0 ? We've heard nothing for months now?

; )
 

JoseJones

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Looks like 8k gaming & VR at 120/144 fps may require PCIe 5.0



PCIe-chart.jpg
 

Sycraft

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I wouldn't worry about it.

For one, you aren't getting 4k@120fps+ anytime soon on mainstream games. The hardware just isn't going to take that big a jump. I mean right now you take the big hitter, the 1080Ti and it only averages 50-60 in most AAA games at 4k. It isn't likely that Votla is going to straight out double or more the performance which is what you'd need, and ti also isn't likely that games will sit still and require the same resources as they do now.

However the other thing to keep in mind is that resolution and frame rate do not place any load directly on the PCIe bus. Putting more pixels on the screen does not inherently require any more data to be transferred to the GPU. When you rasterize more detail in a scene, that is all on the GPU's memory and ROPs, the scene data is the same either way. The PCIe bus is only hit when data is being loaded from main memory to the GPU. Once the scene is on the GPU it isn't touched. So it isn't a matter of how high your res or framerate is, it is a matter of how complex your scene is and more importantly how often you need to get new data for it in.

I think if you test it (and you can, you can slow down your PCIe slots) you'll find that bus bandwidth isn't what's holding you back from ultra high rez gaming, it is ROP and memory performance on the GPU itself.

All that aside, you realize this will need a new generation of computer hardware to use. No existing CPU or board will support it, interconnects aren't something you can upgrade in software or firmware. You'll need a new, as of yet unreleased, CPU and motherboard. Skylake-X isn't going to support it.
 

KazeoHin

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Yeah, the PCI-E bus has more to do with engine detail levels, draw calls, texture size, GPU/CPU crosstalk... resolution is not even slightly affected by PCI-E bandwidth...
 

Nebell

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For one, you aren't getting 4k@120fps+ anytime soon on mainstream games. The hardware just isn't going to take that big a jump. I mean right now you take the big hitter, the 1080Ti and it only averages 50-60 in most AAA games at 4k. It isn't likely that Votla is going to straight out double or more the performance which is what you'd need

I wouldn't bet on it :)
1080Ti is equal to 980Ti SLI, and while it's not double performance, it's still a big leap (and actually smoother to play since there are less low dips). I'm pretty sure that the next card will be able to run most games at 90hz @ 4k and less demanding ones at 120hz and the generation after most games at 120hz @ 4k.
The games will become more demanding, but it's almost only Ubisoft games you need to worry about.
 

spine

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Yeah, the PCI-E bus has more to do with engine detail levels, draw calls, texture size, GPU/CPU crosstalk... resolution is not even slightly affected by PCI-E bandwidth...

Exactly?!

You could have a GPU on a 1x PCIe slot, but instruct it to generate a 8K 4:4:4 120hz signal no problem, wherein the output connector/protocol becomes the limitation.
 

JoseJones

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JoseJones

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Jun 6, 2012
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602
A friend and I were discussing this issue with PCIe and figured - it would be helpful if we knew how much of the PCI bandwidth was being used so, it would be helpful to have a graph like in task manager to be able to monitor how much of the PCI bandwidth is being consumed - we don't know if we are using 45% or 95% of the total bandwidth. Maybe we should be able to monitor that? - just saying.

Yeah, it just makes sense at this point in time to be able to monitor how much of the PCI bandwidth we are using. The charts are not helpful at all to the average person - how ya suppose to take the chart below and the specs for your system and really figure out your bandwidth usage?

pcie-bw-table.jpg


http://techreport.com/news/32064/pcie-4-0-specification-finally-out-with-16-gt-s-on-tap
 
Last edited:

gsilver

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Oct 12, 2010
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Since when do we push out uncompressed video via the PCI-E bus?

It's all out the display connectors...

//Stupid topic
 

Gideon

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PCI 3.0 is not fully saturated yet, 4.0 is coming and likely will be far more then we need for awhile.
 
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