Hello all, first post here on STH, but i've lurked quite a bit.
I participate in the SETI@home project, and I'm doing some brainstorming on a possible new build. So I would like to ask your opinions on some setups. I apologize if this belongs in another forum, but I am not sure which one would be a better fit.
Anyway, I have built a number of multi-gpu setups on SETI, most being only 2-3 GPU setups and are of little concern as it relates to PCIe power. i have another system with a normal consumer motherboard, 7 GPUs and "mining" style USB risers, which provide external power, so no issue with power there as well.
I'm thinking of a new 10-GPU setup using the Supermicro X9DRX+-F motherboard. it would not be used in a normal chassis most likely, but more as an open air setup. The reason for this choice is several fold. First, it supplies 10x PCIe 3.0 x8 slots. While SETI can run OK with just a single PCIe 3.0 lane (as is on my 7-GPU host), there is a slight slowdown vs having 8-16 lanes. the other thing i need to consider is that for best performance, i need at least one CPU-thread per GPU. my 7-GPU host is running on an i7-7700k with 8 threads, so even if i could attach more GPUs, performance would suffer past 8 GPUs. with the X9DRX, i would likely use something like 2x E5-2637v2 for 16 threads and all PCIe lanes.
my conundrum is as follows. I can't find any quality PCIe risers that provide BOTH external power, and 8 PCIe lanes. all of the risers that provide adequate power, only carry one shielded PCIe lane (via USB cable), and all the shielded risers that carry 8 lanes, do not have external power. I have only found ONE riser that seems to do both, but it is unshielded (not sure it would safely handle 3.0 signals), and of questionable quality. see here: PCI-Express PCI-E 8X to 16X Riser Card Flexible Ribbon Extender Cable w/Molex + Solid Capacitor
second option, using unpowered risers. which i could get, and let all cards pull their power from the PCIe slots. I have concerns that this board cannot supply enough power for 10x GPUs this way. this motherboard does provide 2x 8-PIN CPU power, as well as an additional 4-pin power connection. but from my reading, none of these provide power to the PCIe power plane, and are only for the CPU power. can anyone confirm that? the only connector that "might" would be that lone 4-pin connector, but the documentation doesnt really say where that power goes.i could also inject power to the PCIe ports on the 11th slot with something like the EVGA Power Boost, but again i dont know if this would supply enough extra power to satisfy the potential power requirements. see here: EVGA Power Boost
my ideal option would be to use a shielded 8x PCIe riser WITH power connection, but it doesn't look like one exists. if someone knows of one, can you link to it?
thanks
I participate in the SETI@home project, and I'm doing some brainstorming on a possible new build. So I would like to ask your opinions on some setups. I apologize if this belongs in another forum, but I am not sure which one would be a better fit.
Anyway, I have built a number of multi-gpu setups on SETI, most being only 2-3 GPU setups and are of little concern as it relates to PCIe power. i have another system with a normal consumer motherboard, 7 GPUs and "mining" style USB risers, which provide external power, so no issue with power there as well.
I'm thinking of a new 10-GPU setup using the Supermicro X9DRX+-F motherboard. it would not be used in a normal chassis most likely, but more as an open air setup. The reason for this choice is several fold. First, it supplies 10x PCIe 3.0 x8 slots. While SETI can run OK with just a single PCIe 3.0 lane (as is on my 7-GPU host), there is a slight slowdown vs having 8-16 lanes. the other thing i need to consider is that for best performance, i need at least one CPU-thread per GPU. my 7-GPU host is running on an i7-7700k with 8 threads, so even if i could attach more GPUs, performance would suffer past 8 GPUs. with the X9DRX, i would likely use something like 2x E5-2637v2 for 16 threads and all PCIe lanes.
my conundrum is as follows. I can't find any quality PCIe risers that provide BOTH external power, and 8 PCIe lanes. all of the risers that provide adequate power, only carry one shielded PCIe lane (via USB cable), and all the shielded risers that carry 8 lanes, do not have external power. I have only found ONE riser that seems to do both, but it is unshielded (not sure it would safely handle 3.0 signals), and of questionable quality. see here: PCI-Express PCI-E 8X to 16X Riser Card Flexible Ribbon Extender Cable w/Molex + Solid Capacitor
second option, using unpowered risers. which i could get, and let all cards pull their power from the PCIe slots. I have concerns that this board cannot supply enough power for 10x GPUs this way. this motherboard does provide 2x 8-PIN CPU power, as well as an additional 4-pin power connection. but from my reading, none of these provide power to the PCIe power plane, and are only for the CPU power. can anyone confirm that? the only connector that "might" would be that lone 4-pin connector, but the documentation doesnt really say where that power goes.i could also inject power to the PCIe ports on the 11th slot with something like the EVGA Power Boost, but again i dont know if this would supply enough extra power to satisfy the potential power requirements. see here: EVGA Power Boost
my ideal option would be to use a shielded 8x PCIe riser WITH power connection, but it doesn't look like one exists. if someone knows of one, can you link to it?
thanks