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Title: ONE PCIE cable for two GPU's? Post by: BTC22 on February 10, 2018, 09:12:05 PM Right now, I have two PSU's powering 6 GPU's. 5 1080's and one 1070ti. The reason is, the first PSU I bought ( I didn't realize) only had 4 PCIE connectors, so I had to get another PSU. The second one only has two PCIE connectors (750W). I came across a good deal (actual MSRP) on a 1080ti. My question is, do I need to upgrade that second PSU or is there a way to connect it using what I have?
Title: Re: ONE PCIE cable for two GPU's? Post by: halker2010 on February 11, 2018, 03:05:28 AM Right now, I have two PSU's powering 6 GPU's. 5 1080's and one 1070ti. The reason is, the first PSU I bought ( I didn't realize) only had 4 PCIE connectors, so I had to get another PSU. The second one only has two PCIE connectors (750W). I came across a good deal (actual MSRP) on a 1080ti. My question is, do I need to upgrade that second PSU or is there a way to connect it using what I have? you need to get a decent PSU to run them in the standard method other than that its dangerous do not try to do something stupid and damage your card the only alternative is to find IDE or SATA cable to PCI E but even then you might see some decrease in hashrate if you can afford a decent PSU just get one if not try finding one of those cables.Title: Re: ONE PCIE cable for two GPU's? Post by: BTC22 on February 11, 2018, 07:37:05 PM Right now, I have two PSU's powering 6 GPU's. 5 1080's and one 1070ti. The reason is, the first PSU I bought ( I didn't realize) only had 4 PCIE connectors, so I had to get another PSU. The second one only has two PCIE connectors (750W). I came across a good deal (actual MSRP) on a 1080ti. My question is, do I need to upgrade that second PSU or is there a way to connect it using what I have? you need to get a decent PSU to run them in the standard method other than that its dangerous do not try to do something stupid and damage your card the only alternative is to find IDE or SATA cable to PCI E but even then you might see some decrease in hashrate if you can afford a decent PSU just get one if not try finding one of those cables.I figured as much. I guess Im going to upgrade the PSU again, even though I just bought it three weeks ago. Title: Re: ONE PCIE cable for two GPU's? Post by: philipma1957 on February 11, 2018, 07:40:56 PM Right now, I have two PSU's powering 6 GPU's. 5 1080's and one 1070ti. The reason is, the first PSU I bought ( I didn't realize) only had 4 PCIE connectors, so I had to get another PSU. The second one only has two PCIE connectors (750W). I came across a good deal (actual MSRP) on a 1080ti. My question is, do I need to upgrade that second PSU or is there a way to connect it using what I have? you need to get a decent PSU to run them in the standard method other than that its dangerous do not try to do something stupid and damage your card the only alternative is to find IDE or SATA cable to PCI E but even then you might see some decrease in hashrate if you can afford a decent PSU just get one if not try finding one of those cables.I figured as much. I guess Im going to upgrade the PSU again, even though I just bought it three weeks ago. get this one http://www.corsair.com/en-us/rmx-series-rm1000x-1000-watt-80-plus-gold-certified-fully-modular-psu-na-refurbished Title: Re: ONE PCIE cable for two GPU's? Post by: BitMaker2017 on February 12, 2018, 06:55:33 AM You can use CPU power connector from one of your PSUs to get 2 more PCIe power connectors with special splitter cable (price is about $5 on ebay).
Title: Re: ONE PCIE cable for two GPU's? Post by: shimpa on February 12, 2018, 07:28:59 AM you can but don't do it.
Most PCIe cables are AWG16 (better ones are AWG14) and they're rated at 13 amps. 13A * 12V = 156W. That's the maximum power that's safe to draw using those cables. If you use 1 cable for 2 cards you're asking for trouble, those cables might catch fire. Title: Re: ONE PCIE cable for two GPU's? Post by: MasscoinDev on February 12, 2018, 08:31:21 AM Its best not to chance it, just get another PSU. are you planning on getting other cards?
Title: Re: ONE PCIE cable for two GPU's? Post by: COLT601 on February 12, 2018, 10:19:22 AM You can use CPU power connector from one of your PSUs to get 2 more PCIe power connectors with special splitter cable (price is about $5 on ebay). can you post a link to this? will the 2nd power supply still be able to be connected with the dual power supply splitter cable? Title: Re: ONE PCIE cable for two GPU's? Post by: crairezx20 on February 12, 2018, 10:37:45 AM Mostly what i seen in some tutorial in youtube you can use the pcie to 2 gpu this is just what i watched from the youtube tutorial like video from voskcoin
But honestly never tested yet because in my own miner i use only 1 cable per gpu for safety. . You can use CPU power connector from one of your PSUs to get 2 more PCIe power connectors with special splitter cable (price is about $5 on ebay). can you post a link to this? will the 2nd power supply still be able to be connected with the dual power supply splitter cable? You can also get it in amazon but $6 each .. check it here https://www.amazon.com/JBingGG-Graphics-Splitter-Express-Connector/dp/B076D7Q147/ref=sr_1_7?ie=UTF8&qid=1518431358&sr=8-7 I think for 2nd power it would be ok if you use it to power your GPU but i heard a lots of problem about performance and other issue about connector could melt too fast But you can try it if your connector is getting hot just remove it because honestly its not recommended if you really running 24/7 miner.. Title: Re: ONE PCIE cable for two GPU's? Post by: djn053 on February 12, 2018, 02:38:31 PM you can but don't do it. Most PCIe cables are AWG16 (better ones are AWG14) and they're rated at 13 amps. 13A * 12V = 156W. That's the maximum power that's safe to draw using those cables. If you use 1 cable for 2 cards you're asking for trouble, those cables might catch fire. not like this. PEIe cables with 8Pin was 3x12v, so 13*12*3=450w. Are you sure AWG16 can run with 13A? I check some data , AWG16 max is about 6A. so one PEIe with 8pin can only drive 6*12*3=216w. so this is why 1080ti must 8+6pin or 8+8pin Title: Re: ONE PCIE cable for two GPU's? Post by: shimpa on February 12, 2018, 03:30:07 PM you can but don't do it. Most PCIe cables are AWG16 (better ones are AWG14) and they're rated at 13 amps. 13A * 12V = 156W. That's the maximum power that's safe to draw using those cables. If you use 1 cable for 2 cards you're asking for trouble, those cables might catch fire. not like this. PEIe cables with 8Pin was 3x12v, so 13*12*3=450w. Are you sure AWG16 can run with 13A? I check some data , AWG16 max is about 6A. so one PEIe with 8pin can only drive 6*12*3=216w. so this is why 1080ti must 8+6pin or 8+8pin You're right and wrong and I was wrong :) AWG16 max current is 3,7A as per https://www.powerstream.com/Wire_Size.htm My first post was from my head and you're right I didn't take the 3 power leads into consideration. So the correct math is 3,7*3*12=133W per cable. Title: Re: ONE PCIE cable for two GPU's? Post by: BTC22 on February 12, 2018, 04:16:04 PM Right now, I have two PSU's powering 6 GPU's. 5 1080's and one 1070ti. The reason is, the first PSU I bought ( I didn't realize) only had 4 PCIE connectors, so I had to get another PSU. The second one only has two PCIE connectors (750W). I came across a good deal (actual MSRP) on a 1080ti. My question is, do I need to upgrade that second PSU or is there a way to connect it using what I have? you need to get a decent PSU to run them in the standard method other than that its dangerous do not try to do something stupid and damage your card the only alternative is to find IDE or SATA cable to PCI E but even then you might see some decrease in hashrate if you can afford a decent PSU just get one if not try finding one of those cables.I figured as much. I guess Im going to upgrade the PSU again, even though I just bought it three weeks ago. get this one http://www.corsair.com/en-us/rmx-series-rm1000x-1000-watt-80-plus-gold-certified-fully-modular-psu-na-refurbished Thank you. Title: Re: ONE PCIE cable for two GPU's? Post by: BTC22 on February 12, 2018, 04:21:33 PM Its best not to chance it, just get another PSU. are you planning on getting other cards? Im going to say no, but I probably will. Title: Re: ONE PCIE cable for two GPU's? Post by: SCSI2 on February 12, 2018, 06:36:42 PM you can but don't do it. Most PCIe cables are AWG16 (better ones are AWG14) and they're rated at 13 amps. 13A * 12V = 156W. That's the maximum power that's safe to draw using those cables. If you use 1 cable for 2 cards you're asking for trouble, those cables might catch fire. not like this. PEIe cables with 8Pin was 3x12v, so 13*12*3=450w. Are you sure AWG16 can run with 13A? I check some data , AWG16 max is about 6A. so one PEIe with 8pin can only drive 6*12*3=216w. so this is why 1080ti must 8+6pin or 8+8pin You're right and wrong and I was wrong :) AWG16 max current is 3,7A as per https://www.powerstream.com/Wire_Size.htm My first post was from my head and you're right I didn't take the 3 power leads into consideration. So the correct math is 3,7*3*12=133W per cable. I don't know where they got their numbers from (powerstream link above), but it's way off and much lower than expected. Would not trust it because they don't specify temps, insulation type or core count. Here's some better numbers: https://www.engineeringtoolbox.com/wire-gauges-d_419.html (https://www.engineeringtoolbox.com/wire-gauges-d_419.html) Note that your typical (high quality) AWG16 wire would have about 10-15 cores and PVC insulation, so according to chart, it will be fine carrying around 7.0A at 30C ambient. Multiply that by 3x for your typical PCIe power cable and it will result in ~250W at 12V. In practice, I run each 1080ti at 275W powered with one 6-pin PCIe cable + a splitter at the end. -scsi |