Question Can I use 6-pin PCIe cable on 8-pin GPU without adapter?

Sebastian_19

Honorable
May 24, 2016
27
1
10,545
1
hi, I recently purchased a gtx 1070 founders edition. my question is, can I plug a 6 pin pcie power cable to it if the card has 8 pin slot? what would potentially happen if I did such thing? I know there are 6 pin to 8 pin adapters or molex ones, but im just curious how would this end up? would the gpu work?
 
Nope, it would not work. The card can 'sense' that only 6 pin plug has been used and will refuse to start.
Adapters are bad idea - risk of causing fire. Anyway if your PSU does not come with proper 8 (or 6+2) pin cable it probably is too weak to power such GPU so not much sense of using them anyway.
 
I agree. I’ve seen where a molex to sata power adapter started a fire inside a pc and melted the adapter and connectors on the hard drive the adapter connected to. I actually worked on this pc, the inside of the case had black marks from the fire.
 
hi, I recently purchased a gtx 1070 founders edition. my question is, can I plug a 6 pin pcie power cable to it if the card has 8 pin slot? what would potentially happen if I did such thing? I know there are 6 pin to 8 pin adapters or molex ones, but im just curious how would this end up? would the gpu work?
It's not guaranteed that the 6-pin adapter can handle enough current as the 8-pin one, so it's not a good idea to adapt such.

Using a converter can be doable in theory, as long as you know how much power the card is expected to draw over time and how much power the PSU can provide from the connectors you're converting from. If we went from Tom's Hardware's review of the 1070 FE, the card pulls 150W on average, with about 100W coming from the 8-pin connector (it's annoying they used a 3D graph so it's hard to tell exactly where it's floating). Molex connectors can provide up to 11A at 12V, so two of them, in theory, is plenty enough with wiggle room to provide an 8-pin PCIe connector with power. But this also assumes that both the PSU manufacturer and the converter maker did their part in using the correct wire gauge, which cheaper PSUs and converters will likely not have the correct wire gauge.

Anyway, take this information how you will.
 
Reactions: Quanticriver

--SID--

Prominent
Jan 23, 2021
894
189
590
23
hi, I recently purchased a gtx 1070 founders edition. my question is, can I plug a 6 pin pcie power cable to it if the card has 8 pin slot? what would potentially happen if I did such thing? I know there are 6 pin to 8 pin adapters or molex ones, but im just curious how would this end up? would the gpu work?
What make and model PSU do you have?
 
Reactions: Sebastian_19

Bazzy 505

Proper
Jul 17, 2021
249
82
170
4
hi, I recently purchased a gtx 1070 founders edition. my question is, can I plug a 6 pin pcie power cable to it if the card has 8 pin slot? what would potentially happen if I did such thing? I know there are 6 pin to 8 pin adapters or molex ones, but im just curious how would this end up? would the gpu work?
Absolutely no, it will not work with 6 pin, There are adapters sold, but frankly selling them should be illegal. 6 pin connection cannot deliver sufficient current. Bear in mind many of those 6pin adapters use hollow pins. Using those apaters, other than damaging the card, are source of serious firehazard if OC protection on PSU doesn't kick in time, many cheaper PSU don't even have it "really" implemented properly.

The best solution for you to buy an adequate power supply, there are decent ones other there even in 550-650W @ 70-80 bucks that will be a guarantee of safe and happy gamining for many years to come.
 
Well what psu are you using? 6 pin to 8 pin adapters are fine with decent psu and used with only one adapter in total.

Again you'll need to have a decent psu to begin with, the 8 pin connection contains two additional ground pins which somehow enables the connection to provide more power, for specifics maybe someone else could chime in.
 

Bazzy 505

Proper
Jul 17, 2021
249
82
170
4
Well what psu are you using? 6 pin to 8 pin adapters are fine with decent psu and used with only one adapter in total.

Again you'll need to have a decent psu to begin with, the 8 pin connection contains two additional ground pins which somehow enables the connection to provide more power, for specifics maybe someone else could chime in.
and there lays the catch. Any half decent PSU released from 2013 onwards had at least 2pciex cables included ( we're not talking about those shoddy prebuilts that pretend we're still living in 2002).
 
Reactions: spentshells
and there lays the catch. Any half decent PSU released from 2013 onwards had at least 2pciex cables included ( we're not talking about those shoddy prebuilts that pretend we're still living in 2002).
and there lays the catch. Any half decent PSU released from 2013 onwards had at least 2pciex cables included ( we're not talking about those shoddy prebuilts that pretend we're still living in 2002).
No sadly enough. HP and Dell and OEM their own stuff and there are still plenty of new PSU's sporting exactly connectors required to run the best card available for that model.

I laughed there was a guy on here with a 1 year old HP workstation... 700W 2x6 pin, hilarious stuff.
 
Reactions: Bazzy 505

Bazzy 505

Proper
Jul 17, 2021
249
82
170
4
No sadly enough. HP and Dell and OEM their own stuff and there are still plenty of new PSU's sporting exactly connectors required to run the best card available for that model.

I laughed there was a guy on here with a 1 year old HP workstation... 700W 2x6 pin, hilarious stuff.
That's exactly the reason i haven't bought any prebuilt in the last 20 years unless it was laptop or a rackmounted machine, and even there the good choices are getting slimmer by the year.
I used to laugh at the crazy designs on prebuilts in the 90's but looking back, the actual hardware sitting underneath those crazy plastic shells was very reasonable compared to what we see nowdays. I think part of the reason is that typical execs from that era by large came from engineering background, while now it's mostly MBAs.
 
Reactions: spentshells
My psu model is unknown all I have is this

I used to run a gtx 1650 super pefectly on it without issues for months paired with i7-2600
That is 300W PSU, 288W on 12V rail (low quality unit, fire hazard).
GTX 1070 requires 500W psu.

GTX 1650 Super requires 350W. Your psu was barely holding it from blowing up.
Connect GTX 1070 and you'll have oportunity to watch some fireworks.

View: https://www.youtube.com/watch?v=73Px6ANevqw
 
Reactions: Sebastian_19

DSzymborski

Titan
Moderator
My psu model is unknown all I have is this

I used to run a gtx 1650 super pefectly on it without issues for months paired with i7-2600
That is frightening.

And you have no idea that it's running perfectly, only that it hasn't died. Junk PSUs don't just damage parts in dramatic fashion. It's a bit like eating a pound of bacon for breakfast every morning; just because you didn't drop dead today doesn't mean that you're healthy.
 
Reactions: Sebastian_19

DSzymborski

Titan
Moderator
Ok thanks for the answers. I managed to buy a proper 550w psu (thermaltake litepower2) and it seems to work great with the card
Eek. Better than what you have, but that's another very cheap, group-regulated PSU designed to work with PCs that predate the Pentium 4.

One decent budget PSU will be less expensive than buying three or four low-quality ones over the next eight years or so.
 
Reactions: Bazzy 505
just ran a full stress test for around half a hour, nothing bad happened despite the psu being "bad"
There are two factors you are missing here: how long it will work, and how much it will shorten life of your 1070. If you are fine swapping PSU every year or so, and have no problem with not being able to resell that 1070 when you no longer need it (because it will be nearly dead then) then we're good too. After all it's your money.
 

DSzymborski

Titan
Moderator
just ran a full stress test for around half a hour, nothing bad happened despite the psu being "bad"
That's not how any of this works.

This is what testing a PSU looks like. Not running a stress test and shrugging when it doesn't drop dead.



But as it appears you're interested only in the advice you want to hear, this thread isn't for me, so all I can do is wish you good luck.
 

ASK THE COMMUNITY