X570 & Riser Cable Problems for 5700/XT

Dazr87

Average Stuffer
Original poster
May 11, 2019
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So apparently there's issues running the RX 5700/XT on a riser cable or vertical mount when using X570...

X570 Riser Issue

I guess imma have to swap from the Dan case to something else??
 

Dazr87

Average Stuffer
Original poster
May 11, 2019
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Definitely a PCIe 4.0 issue. Need better risers ;-)
Yeah that seems to be the problem. But are there any PCIe 4.0 risers yet?

Also it seems there's no bios option to force/swap to PCIe 3.0 either from the x570s that they've tried
 

dondan

King of Cable Management
DAN Cases
Feb 23, 2015
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I ordered x570, 3700x & 5700 to test it next week. I think it will be not compatible because the total length from the CPU to GPU is longer than 10 inch and the cable has no active retimer component. But it should be possible to change the linkspeed to gen3 in UEFI then it should work. The performance loss is not meassureable.

Regards
Daniel
 

Dazr87

Average Stuffer
Original poster
May 11, 2019
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I ordered x570, 3700x & 5700 to test it next week. I think it will be not compatible because the total length from the CPU to GPU is longer than 10 inch and the cable has no active retimer component. But it should be possible to change the linkspeed to gen3 in UEFI then it should work. The performance loss is not meassureable.

Regards
Daniel
according to their tests on multiple x570 mobos, there was no option to change to gen 3. weird that its not there
 

Legion

Cable-Tie Ninja
Nov 22, 2017
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Yeah that seems to be the problem. But are there any PCIe 4.0 risers yet?

Also it seems there's no bios option to force/swap to PCIe 3.0 either from the x570s that they've tried
The Gigabyte X570 I does indeed have selectable PCI-E x16 slot speed in bios (I'm setting one up right now)
 
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dondan

King of Cable Management
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Feb 23, 2015
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Yes for the Gigabyte x570 ITX there should be the option because it is documented in the manual.

@Legion: Do you have also an AMD 5700 card?
 

Legion

Cable-Tie Ninja
Nov 22, 2017
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Yes for the Gigabyte x570 ITX there should be the option because it is documented in the manual.

@Legion: Do you have also an AMD 5700 card?
Only cards I have here are a 1660ti and a 2080, I will test them with risers though hopefully tomorrow sometime.
 

Dazr87

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May 11, 2019
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Excuse the potato phone pic, I'm just trying to get this setup then I can start having some fun with it. Only got a 3600 (non X) to play with right now, got a 3700x coming in a few days ;)
is it possible to limit TDP in that BIOS? I got the 3900X for my Dan but not sure the Black Ridge is gonna cut it and I dont wanna liquid cool, so I'll grab the C7G later on, hopefully that will be enough
 

deadline

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Aug 9, 2018
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Excuse the potato phone pic, I'm just trying to get this setup then I can start having some fun with it. Only got a 3600 (non X) to play with right now, got a 3700x coming in a few days ;)
Thank you man, seems to me the BIOS is nice and tidy to work in. Will get mine this weekend! 😎
 

dondan

King of Cable Management
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Feb 23, 2015
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Btw I talked with Dmitry from Hardwarecanuks and he told me they used a Fractal Design Define S2 so I think they used a Fractal Design Flex VRC-25 riser.

@deadline Currently there is no PCIe 4.0 riser available. With a bit of luck it will work with the A4-SFXv4 because of it short length. I will test it.

Here are some details from the A4-SFX thread:
Every data connection has two limiting factors shielding and wire length/connection count. If the shielding is bad you have cross talk between two close data wires or external influces that can corrupt the data packages. PCIe 4.0 has very high frequencies that limit the signal length because after some inches the signal and clock is out of shape, also every physical connection reduce the signal quality so you need a retimer or redriver to rebuild it.



The max length for PCIe 4.0 is 10inch this is 254mm. The A4-SFXv4 riser is 185mm so we have ~70mm from CPU to PCIE socket and GPU to riser socket. There is a bit of hope that this will work. With a bit of luck the Gigabyte x570 ITX has a retimer infront of the PCIe socket than it could be work.
 
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Legion

Cable-Tie Ninja
Nov 22, 2017
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is it possible to limit TDP in that BIOS? I got the 3900X for my Dan but not sure the Black Ridge is gonna cut it and I dont wanna liquid cool, so I'll grab the C7G later on, hopefully that will be enough


Yes, it's all configurable, you can tune to whatever you want.
As I said, I'm just in the process of setting up here. I haven't had any time at all yet to do anything other than just finishing up installing drivers etc
 
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Dazr87

Average Stuffer
Original poster
May 11, 2019
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Yes, it's all configurable, you can tune to whatever you want.
As I said, I'm just in the process of setting up here. I haven't had any time at all yet to do anything other than just finishing up installing drivers etc
oh sweet. I may have luck with the 3900X in my Case after all... Any tips from anyone would be appreciated. This is my first SFF build and my first pc build in about 15 years lol
 

firewolfy

Master of Cramming
Nov 12, 2015
379
727
Latest tweets by @hardwarecanucks say they found an option in the MB bios to change the PCIE gen setting. So that is good.

I touched base with Li-Heat (makes the riser for the MI-6 and others). They are testing their risers, but did mention that the 3M riser up to 300mm long seems to boot in gen4.0, so there is a way to get there.

I'll be researching X500 series MBs to see if any of them are locked at gen4.0. If all the popular brands have a switchable PCIE gen setting, than this whole issue should go away (as far as GPUs are concerned anyway).
 
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