Question regarding split pcie cables.

xnikx

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Easy question here. So im wondering if there is any negative to using a single pcie cable that splits into two 6+2 versus using two separate 6+2 pcie cables. Is it safe to use a power cable, such as the one below, to power a high end gpu such as a the 2080 rtx? Or is it recommended that you use two separate pcie cables that run from the psu?

thank you

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Ok thank you. I suppose I should of been more specific as to why I'm asking. I just recently got my Aorus 2080 Extreme and my pc has been crashing during gaming. No blue screen, it just shuts down and restarts. I have run furmark and prime95 with no crashing. It is similar to when my AX1200i went out, but my asus board would post a screen saying something was wrong with the power supply so I knew what the issue was.

I ran my 1080 strix on the single split cable and never had any issues. I'm trying to rule out if this could be whats causing the crash. Currently i cant test as I'm doing a clean install of windows to rule out any software issues.
 
Ok thank you. I suppose I should of been more specific as to why I'm asking. I just recently got my Aorus 2080 Extreme and my pc has been crashing during gaming. No blue screen, it just shuts down and restarts. I have run furmark and prime95 with no crashing. It is similar to when my AX1200i went out, but my asus board would post a screen saying something was wrong with the power supply so I knew what the issue was.

I ran my 1080 strix on the single split cable and never had any issues. I'm trying to rule out if this could be whats causing the crash. Currently i cant test as I'm doing a clean install of windows to rule out any software issues.
well add the other cable after the reload and see how it acts. that will rule it out. is it still the same sig system just a new psu?
 
well add the other cable after the reload and see how it acts. that will rule it out. is it still the same sig system just a new psu?

No i need to update that. I'm doing a completely new upgrade but I'm waiting on my i9 9900k.

This is my current setup.

Asus Rampage IV Extreme
Gigabyte Aorus 2080 RTX Extreme
i7 3930k (at stock speeds, was trying to rule out the overclock)
G.SKILL Ripjaws Z Series 16GB DDR3 1600mhz
EVGA 750 G3
Samsung 850 EVO 1TB
 
My question is why? The evga 750w g3 has six 6+2 pcie connectors.
Does your PSU harness have a female connector to use the one shown? Or was it just a rough example?
 
My question is why? The evga 750w g3 has six 6+2 pcie connectors.
Does your PSU harness have a female connector to use the one shown? Or was it just a rough example?
that was an example I guess. the evga ones are sleeved the that black mess stuff. I assume he want less cable clutter.
 
The cables are rated for about 75W each, with a fairly low voltage drop. (depending on vendor.)

I would use two seperate cables, to minimize the voltage drop, the additional load on the cable makes for downward voltage 'spikes' in the power, every time the load increases, and that's not even talking about the inductance of the cable at the frequencies the on-card power supply is drawing power.

Adding the second cable decreases the resistance by half, and the inductance by half, So I'd go that route.

Using a cable that's too small will cause the power supply to overreact, and can kill both supply and downstream power supply.


I once had to run a 120A average power connection at 3.3V 30 feet, with less than .5V of drop for an MR device. The resulting cable was bigger than a 50Cent piece (350MCM), and had to be shielded for RF. :)
 
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The cables are rated for about 75W each, with a fairly low voltage drop. (depending on vendor.)

I would use two seperate cables, to minimize the voltage drop, the additional load on the cable makes for downward voltage 'spikes' in the power, every time the load increases, and that's not even talking about the inductance of the cable at the frequencies the on-card power supply is drawing power.

Adding the second cable decreases the resistance by half, and the inductance by half, So I'd go that route.

Using a cable that's too small will cause the power supply to overreact, and can kill both supply and downstream power supply.


I once had to run a 120A average power connection at 3.3V 30 feet, with less than .5V of drop for an MR device. The resulting cable was bigger than a 50Cent piece (350MCM), and had to be shielded for RF. :)
6pin is 75w, 8pin is 150w.
 
so maybe im wrong, since the 2080 will pull ~200w. maybe it does need both?
 
as someone who has alot of experience blowing up cables, a single 8 pin can do 300w. good wire will do about 260 before it degrades over time due to heat. You can pull the same power from a 6pin as a 8 pin if you want but if the cable is cheap it will slowly melt. there is almost no harm in trying and just feel the cable for heat to see if tis working adequately.

Last cable I prrpersona melted was the PSU end of a single 8 pin powering a entire 295x2 and even that took a month of mining to do
 
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as someone who has alot of experience blowing up cables, a single 8 pin can do 300w. good wire will do about 260 before it degrades over time due to heat. You can pull the same power from a 6pin as a 8 pin if you want but if the cable is cheap it will slowly melt. there is almost no harm in trying and just feel the cable for heat to see if tis working adequately.
I like your test methodology lol. I have similar experience tinkering with high current CC LED systems and it's a similar story.
 
Just an update, been gaming a lot of my two days off here with no crashes. So, hoping the issue was the gpu not getting enough power off a single split pcie cable. I'll report back if I get any crashes but I have over 5 hours of gaming with no crashing.
 
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