Z390 Motherboard with PCIe 3.0 supports RX 5700?

[Tiffanysinyee]

Do the Z390 chipset and motherboards support PCI Express 4.0?  If they don't, then building a rig with RX 5700 will be a waste of the graphics board's power, it will be under-utilized.

[Jurrunio]

10 minutes ago, Tiffanysinyee said:

If they don't, then building a rig with RX 5700 will be a waste of the graphics board's power, it will be under-utilized.

This is completely wrong, don't say it as if it's a fact.

https://www.techpowerup.com/review/pci-express-4-0-performance-scaling-radeon-rx-5700-xt/24.html

1-2% is totally within margin of error.

[Fasauceome]

PCIe 4.0 isn't relevant for gaming yet so don't worry about losing performance from bandwidth being reduced. All PCIe revisions are intercompatible so 3.0 buses work with 4.0 devices and vice versa

[Aperture9999999]

Only AMD's 3rd gen chipset supports PCIE 4.0, so no, Z390 does not support it. I wouldn't worry about the card being underutilized, all those PCIE lanes will not really affect the average consumer. They would be helpful if you do something with a lot of PCIE cards, but otherwise, don't worry about it.

[Tiffanysinyee]

2 minutes ago, Fasauceome said:

PCIe 4.0 isn't relevant for gaming yet so don't worry about losing performance from bandwidth being reduced. All PCIe revisions are intercompatible so 3.0 buses work with 4.0 devices and vice versa

What you mean by saying that PCIe 4.0 is not relevant for gaming?

[Fasauceome]

1 minute ago, Tiffanysinyee said:

What you mean by saying that PCIe 4.0 is not relevant for gaming?

While the RX 5700 series uses PCIe 4.0, doubling the bandwidth, it changes nothing with performance, because there isn't enough data to saturate the bus.

[Tiffanysinyee]

2 minutes ago, TheDragonHawk said:

Only AMD's 3rd gen chipset supports PCIE 4.0, so no, Z390 does not support it. I wouldn't worry about the card being underutilized, all those PCIE lanes will not really affect the average consumer. They would be helpful if you do something with a lot of PCIE cards, but otherwise, don't worry about it.

Let me get it right: you're saying that if I plug a RX 5700 into a PCIe 4.0 slot that only comes with X570 board (Not Z390), the card's total bandwidth will not be utilized or it will?

[Falkentyne]

1 minute ago, Tiffanysinyee said:

What you mean by saying that PCIe 4.0 is not relevant for gaming?

It's not relevant for gaming.

That's what it means.

And PCIE 4.0 was dead in the water before it was even released.

Not even 6 months later, they announced PCIE 5.0. 

 

There are no video cards that will saturate fully PCIE 3.0 yet.  Stop worrying so much.

Maybe when Nvidia's RTX successor comes out, look for reviews, since PCIE 4.0 is being leapfrogged anyway for PCIE 5.0 and then see how it compares.

[Tiffanysinyee]

Just now, Fasauceome said:

While the RX 5700 series uses PCIe 4.0, doubling the bandwidth, it changes nothing with performance, because there isn't enough data to saturate the bus.

Sorry, I still don't get it.  If RX 5700 uses PCIe 4.0, and the bus allows data flowing that fast, how come the performance is not increased??

[Fasauceome]

Just now, Tiffanysinyee said:

Sorry, I still don't get it.  If RX 5700 uses PCIe 4.0, and the bus allows data flowing that fast, how come the performance is not increased??

The graphics chip can only process so much data. Jam as much info as you want down the Pipeline, only so much can come out the other end.

 

So to speak 

[Tiffanysinyee]

Just now, Fasauceome said:

The graphics chip can only process so much data. Jam as much info as you want down the Pipeline, only so much can come out the other end.

 

So to speak 

A PCIe 3.0 graphics card doesn't jam the bus do I get it right from you?

[Jurrunio]

1 minute ago, Tiffanysinyee said:

If RX 5700 uses PCIe 4.0, and the bus allows data flowing that fast, how come the performance is not increased??

Just like a fat man trying to run a triathlon, better shoes won't help his poorly trained body last the whole race.

[Fasauceome]

Just now, Tiffanysinyee said:

A PCIe 3.0 graphics card doesn't jam the bus do I get it right from you?

Yes, in fact PCIe 3.0 x16 graphics cards have shown almost no drop in performance when utilized at x8 because even PCIe 3.0 x16 has yet to be saturated by graphics tasks.

[Falkentyne]

1 minute ago, Jurrunio said:

Just like a fat man trying to run a triathlon, better shoes won't help his poorly trained body last the whole race.

You have won the internet award for the day.  Well played, sir.

[Jurrunio]

1 minute ago, Fasauceome said:

Yes, in fact PCIe 3.0 x16 graphics cards have shown almost no drop in performance when utilized at x8 because even PCIe 3.0 x16 has yet to be saturated by graphics tasks.

2080ti is breaking PCIe 3.0 x8, next gen will see PCIe 4.0 I can assure

[Tiffanysinyee]

3 minutes ago, Jurrunio said:

Just like a fat man trying to run a triathlon, better shoes won't help his poorly trained body last the whole race.

Appreciate your effort, can you make a simpler analogy...

[Tiffanysinyee]

2 minutes ago, Fasauceome said:

Yes, in fact PCIe 3.0 x16 graphics cards have shown almost no drop in performance when utilized at x8 because even PCIe 3.0 x16 has yet to be saturated by graphics tasks.

Ok, let me try again...

 

So the onboard PCIe lane is this wide, and from the card to the board is all clear;

Now when the RX 5700 (PCIe 4.0) kicks in, and the game requests transferring X amount of data from the card to the board through the lane, the lane is choked because the X amount of data is too much, do I understand you correctly?

[Mathieu9836]

Current GPUs barely fill PCIE X8 gen 3 (2080TI), how PCIe gen 4 is supposed to make it faster?

[Tiffanysinyee]

5 minutes ago, Jurrunio said:

2080ti is breaking PCIe 3.0 x8, next gen will see PCIe 4.0 I can assure

Don't get it still, sorry maybe it's my sillyness.

[Fasauceome]

2 minutes ago, Tiffanysinyee said:

Now when the RX 5700 (PCIe 4.0) kicks in, and the game requests transferring X amount of data from the card to the board through the lane, the lane is choked because the X amount of data is too much, do I understand you correctly?

not necessarily, because the 5700's GPU won't be transferring a full PCIe 4.0 bus worth of data, so it wouldn't choke. In theory you have the right idea, but only if the amount of data the 5700 can process is above what a PCIe 3.0 lane can carry. What I'm saying is that a 5700 with PCIe 3.0 would behave the same way because it does not have a performance level that is above current gen graphics cards, i mean the 2060 super, its competitor, still uses PCIe 3.0 and it's not choked.

[Jurrunio]

2 minutes ago, Tiffanysinyee said:

Appreciate your effort, can you make a simpler analogy...

No. Basically because 5700XT's performance bottleneck is not by PCIe (it's the VRAM, as shown by overclocking), more bandwidth there doesn't help it.

 

1 minute ago, Tiffanysinyee said:

the lane is choked because the X amount of data is too much

this is where you get wrong. I came up with another analogy, a bigger mailvan won't speed up delivery when the small mailvan already carries all mail in one go.

[Tiffanysinyee]

Just now, Fasauceome said:

not necessarily, because the 5700's GPU won't be transferring a full PCIe 4.0 bus worth of data, so it wouldn't choke. In theory you have the right idea, but only if the amount of data the 5700 can process is above what a PCIe 3.0 lane can carry.

So you're saying that at a particular instant, the 5700 is requested to carry X amount of data through a PCIe 3.0 lane supporting (x16/x8/x4), but that exceeds the bandwidth that the lane allows, so the performance gets slowed down, am I correct?

[Tiffanysinyee]

4 minutes ago, Jurrunio said:

No. Basically because 5700XT's performance bottleneck is not by PCIe (it's the VRAM, as shown by overclocking), more bandwidth there doesn't help it.

 

this is where you get wrong. I came up with another analogy, a bigger mailvan won't speed up delivery when the small mailvan already carries all mail in one go.

Drawing analogy is not an easy try dear Jurrunio....

[Mathieu9836]

The issue is how much data can be processed by the GPU, not how fast the data is transfered through PCIe Lanes.

[Fasauceome]

8 minutes ago, Tiffanysinyee said:

at a particular instant, the 5700 is requested to carry X amount of data through a PCIe 3.0 lane supporting (x16/x8/x4), but that exceeds the bandwidth that the lane allows, so the performance gets slowed down, am I correct?

I'm saying you would be correct, but the 5700 does not do that, because it can't handle that much data. The 5700 does not exceed a PCIe 3.0 X16 bus worth of data despite the fact that it uses PCIe 4.0.