bob16314
I see..Well, if you wanna you can easily remove the terminals from the graphics card connector and rearrange them according to the pinout below which is industry-standard..Use a paper clip/pin/needle/whatever to depress the locking tabs on the terminals and pull them out, but bend them back up..You can borrow from somebody, or buy an el cheapo digital multimeter at big box stores, hardware stores, auto parts stores, Amazon for about $10 that will do to check the power and ground pinout..Or you could take your PC/PSU to a repair shop and have them re-pin the connector..Or buy another PSU with the needed/correct connectors.

The pinout is shown as if you're looking into the end of the connectors..PCIe 8pin is the same as 6+2pin, the extra two pins are grounds.

MZ6Z0
So I just purchased a new GTX 1070 and whenever I start up my computer, the screen tells me to power down and connect the PCIe cables to the graphics card. The PCI cables I got were one 8 pin connector.
My power supply unit (PSU) is an Antec 620, and it requires a 10 pin connector, but the power cables I got with my graphics card were incompatible, so I bought a new one. I bought a power cord with a 10 pin connector (goes into my PSU) on one side and an 8 pin connector (goes into graphics card) on the other. They connect, but my computer does not start up at all when they are connected. When I disconnect them and start up, my computer starts up and I receive the same error message.

I am very new to this, so I will need a lot of help

bob16314

HeavyHemi
Bob, it is not the end that plugs into the GPU that is the issue. Those are all wired identically. It is where it the PCIe power plugs into the PSU where the pinout varies.  You'd need the pinout for the PSU and to reconfigure the connector where it plugs into the PSU.

 

Yes, I know..If the pinout power/ground on the PSU end of the cable are mismatched from what the pinout on the GPU end should be, then you can rearrange the terminals on the GPU end to the way they should be in the pinout diagram..As long as the industry-standard pinout power/ground on the GPU end is correct, it will work as it should..And as always, never use cables from another PSU unless they are documented/proven compatible.

In other words, if the pinout power/ground is wrong on the PSU end, it will be wrong on the GPU end too..You can just rearrange the terminals on GPU end correctly.

An Antec High Current Gamer HCG-620M does not have hardwired PCIe cables, they go to a modular 10pin.

If a Dual Molex to PCIe Adapter was included with the GTX 1070, that can be used.
 

bob16314
As long as the power and ground terminals on the GPU end are correct according to the industry-standard pinout and confirmed with a voltmeter, that's all that matters, and they can be rearranged as needed..There's only 12V and Ground..It's really not difficult.
 
The OP said he lost/can't find the PCIe cables that came with the PSU.

bob16314
Hemi..If the PCIe cable wiring is wrong on the PSU end, the GPU plug end will be wrong also, that's just common sense..Repin the GPU plug so the power and ground terminals in it are right..Simple..Been there done that.

The only issue that might be is that if the 10pin is double wired to an 8pin PCIe terminal where a power and a ground wire are going to the same pin..Cut/remove the offending wire.

As long as power/ground in the PCIe end is right, that's all that matters..Maybe basic electrical wiring and how to check polarity with a digital multimeter and fix stuff is too much for some ppl here..I guess I shouldn't assume that what's child's play for me is rocket science for some others.

See the quote at the bottom of my signature.