Unable to detect 2nd GPU on PCI Riser

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   @kerberos_20 depends on the riser. The more premium USB style risers typically already have PCI-E presence short on the PCB itself. Regular ribbon style risers will need a presence short depending on the slot used and motherboard. Some video cards may not work at all, even with presence short. I had a number of AMD cards that were hit-and-miss with detecting, thought it was dodgy risers, bad connection. Using the same board and risers and a bunch of nvidia cards later, each one detected flawlessly on the first shot.

There is usually not any option in motherboard BIOS/setting to change behavior OP. PCI-E Gen 1/2/3 makes no difference. The slot and device will negotiate the fastest generation and widest path that is physically supported. This is why some PCI-E 1x/4x slots have an open end on it so you can plug in pci-e card with more phyiscal pci-e lanes, and why you can plug in an old geforce 6800 ultra pci-e 1.0 card on a modern board or geforce gtx 1080 ti on an old x38 motherboard.

Edited by ssateneth - 22 May 2018 at 10:55am

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
ssateneth Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 19 Oct 2017 Status: Offline Points: 129	Post Options Post Reply Quote ssateneth Report Post Thanks(0) Quote Reply Topic: Unable to detect 2nd GPU on PCI Riser Posted: 22 May 2018 at 10:51am
	@kerberos_20 depends on the riser. The more premium USB style risers typically already have PCI-E presence short on the PCB itself. Regular ribbon style risers will need a presence short depending on the slot used and motherboard. Some video cards may not work at all, even with presence short. I had a number of AMD cards that were hit-and-miss with detecting, thought it was dodgy risers, bad connection. Using the same board and risers and a bunch of nvidia cards later, each one detected flawlessly on the first shot. There is usually not any option in motherboard BIOS/setting to change behavior OP. PCI-E Gen 1/2/3 makes no difference. The slot and device will negotiate the fastest generation and widest path that is physically supported. This is why some PCI-E 1x/4x slots have an open end on it so you can plug in pci-e card with more phyiscal pci-e lanes, and why you can plug in an old geforce 6800 ultra pci-e 1.0 card on a modern board or geforce gtx 1080 ti on an old x38 motherboard. Edited by ssateneth - 22 May 2018 at 10:55am
	MB: X399 Taichi, UEFI L3.32 VGA: EVGA 1080 Ti FTW3 PSU: Seasonic PRIME 1300 W PLATINUM CPU: AMD Ryzen Threadripper 2950X MEM: 4x16GB, 3600MHz G.Skill Trident Z F4-3600C17Q-64GTZKW

ericlaiys Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 20 May 2018 Status: Offline Points: 5	Post Options Post Reply Quote ericlaiys Report Post Thanks(0) Quote Reply Posted: 21 May 2018 at 6:13pm
	Do i need to set anything on mobo to detect card on PCIE? How about set to Gen 1 rather than auto?

ericlaiys Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 20 May 2018 Status: Offline Points: 5	Post Options Post Reply Quote ericlaiys Report Post Thanks(0) Quote Reply Posted: 21 May 2018 at 6:12pm
	hmm... i tried use on other motherboard, it is working fine & able to detect. my pci riser is using this one:- https://www.lazada.com.my/products/jvgood-pcie-ver-006-pci-e-16x-to-1x-powered-riser-adapter-card-w-60cm-usb-30-extension-cable-molex-to-sata-power-cable-gpu-riser-adapter-ethereum-mining-eth-2-mintcell-cable-ties-i162521854-s193682030.html?spm=a2o4k.searchlist.list.1.64b37b11IGZPi3&search=1 That would be difficult as most seller dont tell if it include with A1-B17.

kerberos_20 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 06 Dec 2017 Location: czech republic Status: Offline Points: 3687	Post Options Post Reply Quote kerberos_20 Report Post Thanks(0) Quote Reply Posted: 20 May 2018 at 4:28pm
	To get some mobos to detect gpus using 1x risers u have to short some presence pins on the pci express slot. I believe it was A1 to B17. some risers have that A1-B17 short built-in to them already. You can check with an ohmmeter.
	userbenchmark

ericlaiys Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 20 May 2018 Status: Offline Points: 5	Post Options Post Reply Quote ericlaiys Report Post Thanks(0) Quote Reply Posted: 20 May 2018 at 1:21pm
	Hi, Had AB350 Pro4 with 600w PSU & using Ryzen 3 2200G. MB using latest firmware 4.7. Got 1 unit of GTX 1060 6GB 1 unit of GTX 1050 Ti 4GB Able to detect AMD integrated, GTX1050 (installed on PCI2 directly on motherboard) and GTX 1060 (installed on PCI1 using PCI Riser) Problem is when i took out GTX1050 and use it on PCI Riser, i cannot detect this card in any PCI Slot. Only work when plug into the motherboard. Any idea why this is happening?