General Discussions

[alikey]

PCIE gen 4 is coming out with the new x570 motherboards, and I have seen on the web quite a few conversations bringing up gen 4's increased susceptibility to resistance over longer cable routes compared to gen 3.  Has anyone heard/read of what gen 4's max extendable distance beyond the PCIE slot will be?  Does anyone know if our current PCIE gen 3 extenders are usable with gen 4?

[alikey]

I contacted ASUS, and, while this should not be taken as an official statement from them, their customer support (after having to track down the info) told me that PCIE gen 4’s signal should travel 15 meters away from the source.  So, PCIE 4.0 risers should work fine for ITX builds.  I didn’t ask whether or not gen 3 cables worked for gen 4, but, I’m feeling optimistic.  I’ve seen cables online rated for Gen 4, though, considering there are no real physical differences between gen 3 and 4 cables (as far as I can tell), there is no reason gen 3 shouldn’t work.  It’s still just copper after all.

[nfspeed1995]

Only 3M and LINKUP Extreme riser cables work for Gen4. All others failed to run at PCIE4.0 if BIOS set to GEN4.

[alikey]

I tried one of linkup’s extreme riser cables, which was supposedly pcie 4.0 verified (bought from amazon, seller was linkup).  The cable, unfortunately, did not work.  Using it caused my computer to crash on a regular bases.  Maybe 3M works?  I haven’t tried them yet.  I’m using a 3600 cpu, Aorus x570 I pro wifi motherboard, and the 5700 xt AE gpu.  Everything works as long as no riser cable is used.  This holds true for linkup’s extreme riser cable.

[nfspeed1995]

There is a youtube video showing 3DMark PCIE features test on LINKUP

Extreme PCIE 4.0 50cm riser cables. It shows more than 20GB/s as most Gen 3

only runs at 12GB/s.

You can search youbute on "LINKUP Extreme 50cm Riser Cable + Gigabyte X570

+ RX5700XT".

[elstaci · Accepted solution]

Found this website that mentions lengths for various flexible extender cables: FAQ.HTM 

From this Thread concerning your question: https://smallformfactor.net/forum/threads/x570-riser-cable-problems-for-5700-xt.11113/ 

[alikey]

Thanks elstaci.  I, for the life of me, couldn’t find this PCIE change option in the BIOS.  The link you gave me details exactly where to find it.  I’m kinda sad that none of the extension cables I have work with gen 4 PCIE, but, at least I can use ‘em with gen 3 now (pending some other problem, as, I haven’t actually switched the option and tested the cable with it switched yet).  I hope that they find a way to make gen 4 work with riser cables, but, the image you provided with the red underlined text seems to be correct as far as my experience tells me, meaning (in answer to the question I posed above): Current gen 3 risers DO NOT work with gen 4, and, the max length from the PCIE slot that a gen 4 cable could be is dependent on if a signal repeater is near the PCIE port on the motherboard.

[nfspeed1995]

Hi Alikey,

Just bought LINKUP extreme 30cm. I got 20GB/s on 3DMark PCIE Feature test with BIOS setup to Gen4 on my system. Ryzen 3900X + X570 Gaming X + Radeon XR5700 XT. If I setup Gen 3 on bios, the speed down to 12GB/s on the 3DMark. I also ran stress test on Time Spy a few times today. It scores 9015.

What motherboard do you have? Mine is Gigabyte X570 Gaming X.

[alikey]

Hi nfspeed1995,

I have the Gigabyte Aorus x570 I Pro WiFi motherboard, Ryzen 3600 CPU, and 5700 XT AE GPU.  Maybe it’s just my specific motherboard, but PCIE 4.0 mode leads to crashes and extreme instability when using ANY riser cable (including the LINKUP PCIE 4.0 Verified Riser cable).  All the riser cables I have work on my z390 phantom gaming itx motherboard combined with the 5700 xt AE (running in PCIE 3.0 of course, as 4.0 isn’t available for that board).  If it works for you, then I guess PCIE 4.0 can use the new risers, but I have no clue why they’re giving me so much trouble.

[nfspeed1995]

Okay. I am getting my Gigabyte M/B replaced wit hAorus X570 I Pro Wifi motherboard. See what would happen. Hope Amazon has one for sale.

I will let you know.