PCIe 5.0?

[Taf the Ghost]

One thing is CPUs have to be designed with PCIe 4.0 lanes. While I don't doubt it's too big of a design difference, it still takes time.  Along with updates to Chipset and all of the design specs for the Mobo manufacturers. Physical hardware is supposed to arrive this year, but late 2018 is the absolute earliest we'd see it in an Intel CPU.  (AMD is on AM4 until at least 2020, though a revision to the TR or Epyc lines could see it in 2019.)

 

There's also the issue that there's a lot of industry working groups looking into other directions for interconnects, especially as what really needs higher speed connections is fairly specific types of hardware.  It could mean moving things like Networking off to another type of interface.

[Prysin]

7 hours ago, PiGHamM3R said:

PCI-SIC accelerates the creation of PCIe 5.0

 

 

Source: https://www.overclock3d.net/news/misc_hardware/pci-sic_accelerates_the_creation_of_pcie_5_0/1

 

 

PCIe 5.0 will enable users to get more bandwidth out of fewer PCIe lanes and enable the creation of faster PCIe devices, allowing 400Gb/s Ethernet solutions to be created for servers or to reduce the PCIe requirements of modern M.2, U.2 or PCIe storage devices. 

 

 

So with GPUs not even saturating the bandwidth of a current 3.0 x16 slot, I can only wonder what this will do to SSDs...

 

MOAR POWER!!!!111!!!!!

oh please, black text? FFS

 

Also, modern GPUs doesnt even fully saturate PCIe Gen2 x8 during gaming... litterally 1-2FPs diffference between Gen2 x8 and Gen3 x16 with a 1080... you can google it.

[SansVarnic]

Its Blue ... 

[Doobeedoo]

Oh wow I mean cool though yeah, until that comes heh. But awesome for support of more and new features along faster bandwidth too.

GPUs and NVMe SSDs for now are pretty good on current gen.

[paddy-stone]

What I take form this, is that with the way current gen pci lanes are used, eg x16 x8 etc, it might be beneficial to start having them like x4 x4 etc, and so if the powers that be limit pci-e lanes for boards as they currently do, people shouldn't have to choose between using an x16 card and only having one pci-e x4 m.2 drive for instance if they still have 20 lanes to use, and could instead have x4 x4 for 2 GPUs and still have other pci-e devices. Maybe that's not how it works, or in reality the likes of intel dropping the amount of lanes they have per iteration of motherboards even more maybe?  it's not just intel I know, but there's have probably caused a lot more confusion than AMDs as every iteration of boards and/or CPUs have been different lately and dropped the amount of lanes available.

[NumLock21]

4 hours ago, Sniperfox47 said:

Snip

Physical lanes required by the drive will still be used no matter which pcie gen it's running on.  

[Drak3]

2 hours ago, NumLock21 said:

Physical lanes required by the drive will still be used no matter which pcie gen it's running on.  

It's possible for next generations of PLX chips to route fewer higher bandwidth lanes into the necessary # of lanes of lower bandwidth to circumvent this. If PCIe 4.0 doubles the bandwidth of 3.0, and 5.0 doubles that of 4.0, a single PCIe 5.0 lane and a PLX chip could replicate an x4 3.0 connection, and x2 5.0 would replicate a x8 3.0, and x4 5.0 replicates x16 3.0.

[Sakkura]

14 hours ago, Sniperfox47 said:

They're pushing up PCIe 5.0 specifically because PCIe 4.0 is so iffy right now. There's a very good possibility that on the consumer side we won't even see PCIe 4.0, and it'll jump straight to 5.0 because 4.0 doesn't have much of a benefit to users.

But... wouldn't PCIe 5.0 just be even more iffy?

[NumLock21]

11 hours ago, Drak3 said:

It's possible for next generations of PLX chips to route fewer higher bandwidth lanes into the necessary # of lanes of lower bandwidth to circumvent this. If PCIe 4.0 doubles the bandwidth of 3.0, and 5.0 doubles that of 4.0, a single PCIe 5.0 lane and a PLX chip could replicate an x4 3.0 connection, and x2 5.0 would replicate a x8 3.0, and x4 5.0 replicates x16 3.0.

Only way to find if that theory is true, is to use one of the nvme ssd of today on a future board that uses pcie 5.0. 

 

Current board, nvme ssd at pcie 3.0 x4 

Future board, nvme ssd at pcie 5.0 x1

 

But the problem is, how flexible the pcie lanes are, when it's configured by the motherboard manufacture. Some current boards, the m.2 can be set to x1.

 

 

[Mira Yurizaki]

3 hours ago, Sakkura said:

But... wouldn't PCIe 5.0 just be even more iffy?

Remember GDDR4? There was like only one card that used it. Then everyone just skipped it and went to GDDR5.

[Sniperfox47]

3 hours ago, Sakkura said:

But... wouldn't PCIe 5.0 just be even more iffy?

PCIe 4.0 was iffy because they redid huge parts of the physical layer, in part to ensure that it would be better future proof moving forwards without breaking compatibility with PCIe 3.1 and under.

 

With PCIe 4.0 finally finalized as of yesterday,  we could potentially see products with it implemented as early as later this year.

 

PCIe 5.0 on the other hand is going to be a relatively smaller change so shouldn't be too  bad for them to finalize on time.

 

With two years expected between the standards, relatively smaller benefit for consumers, and the amount of time it will take to start rolling out devices is it really worth it for the likes of AMD and Intel to impliment 4.0 on the consumer side vs just wait for 5.0? I guess we'll see.

 

P.S. I could see it popping up on the ARM side though. This is the first PCIe spec I could see being viable in ChromeOS/Android tablets from a power cost point if view.

[Taf the Ghost]

There's 1 significant difference with 4.0: a new connector. So they'll be able to port over PCIe 3.0 devices to the new connector (as they're electrically backwards compatible), but there is a different physical connector for the expansion cards.  Or we're going to see Motherboards with an 4.0 and 3.0 slot.

 

So we might see a skip to 5.0 in the consumer space if it shows up around 2021, but servers should probably shift over pretty quickly.

[Sniperfox47]

1 minute ago, Taf the Ghost said:

There's 1 significant difference with 4.0: a new connector. So they'll be able to port over PCIe 3.0 devices to the new connector (as they're electrically backwards compatible), but there is a different physical connector for the expansion cards.  Or we're going to see Motherboards with an 4.0 and 3.0 slot.

 

So we might see a skip to 5.0 in the consumer space if it shows up around 2021, but servers should probably shift over pretty quickly.

There's a new connector? When did that change? I haven't yet read the finalized spec but last time I heard it was still planned to be mechanically and electrically compatible?

[Sakkura]

34 minutes ago, M.Yurizaki said:

Remember GDDR4? There was like only one card that used it. Then everyone just skipped it and went to GDDR5.

GDDR5 helped performance and was affordable and straightforward to implement. PCIe 5.0 will be even more unaffordable and difficult to implement than PCIe 4.0, and there's less need for the bandwidth.

9 minutes ago, Sniperfox47 said:

PCIe 4.0 was iffy because they redid huge parts of the physical layer, in part to ensure that it would be better future proof moving forwards without breaking compatibility with PCIe 3.1 and under.

 

With PCIe 4.0 finally finalized as of yesterday,  we could potentially see products with it implemented as early as later this year.

 

PCIe 5.0 on the other hand is going to be a relatively smaller change so shouldn't be too  bad for them to finalize on time.

 

With two years expected between the standards, relatively smaller benefit for consumers, and the amount of time it will take to start rolling out devices is it really worth it for the likes of AMD and Intel to impliment 4.0 on the consumer side vs just wait for 5.0? I guess we'll see.

 

P.S. I could see it popping up on the ARM side though. This is the first PCIe spec I could see being viable in ChromeOS/Android tablets from a power cost point if view.

PCIe 4.0 was iffy because of how fast it's running - already causing issues with trace length and/or needing repeaters. PCIe 5.0 will just make those problems exponentially worse, unless they shift to completely new technology.

[Taf the Ghost]

25 minutes ago, Sniperfox47 said:

There's a new connector? When did that change? I haven't yet read the finalized spec but last time I heard it was still planned to be mechanically and electrically compatible?

I haven't found a news release since that contradicts the new connector information.

[Jito463]

1 hour ago, Taf the Ghost said:

I haven't found a news release since that contradicts the new connector information.

Based on that, existing PCIe 3.0 (and =<2.0?) cards will be compatible with the new connectors, but new cards will not be backwards compatible with existing boards.  We already see that with PCIe 3.0 video cards not working in PCIe 2.0 motherboards, so nothing new there.

[Sakkura]

4 minutes ago, Jito463 said:

Based on that, existing PCIe 3.0 (and =<2.0?) cards will be compatible with the new connectors, but new cards will not be backwards compatible with existing boards.  We already see that with PCIe 3.0 video cards not working in PCIe 2.0 motherboards, so nothing new there.

I've never seen that. PCIe 3.0 cards should work in PCIe 2.0 slots.

[Jito463]

2 minutes ago, Sakkura said:

I've never seen that. PCIe 3.0 cards should work in PCIe 2.0 slots.

I've run into systems that just would not boot with a PCIe 3.0 card in them.  Put in an older PCIe 2.0 card, and they work just fine.  Then again, I just assumed that they were 2.0 slots.  It's possible they were 1.x, instead.

[SpaceGhostC2C]

What I would really like on the consumer side of things is to have an extra layer of flexibility on the PCIe configuration. What I mean is, very few consumer devices require all the bandwidth in the world, but it's good to have it for those. However, if we could split a few high bandwidth lanes into several lower bandwidth slots as needed. There is some of that in current motherboards, but for example if your GPU is fine with 3.0 x8 then at best you can enable a second x8 slot, but you cannot break it down in a more flexible way. I mean, there are soundcards that are good with 2.0 x1, but there is no way to reallocate bandwidth if you plug them in 3.0 x1