Video card PCIe power connectors, 6 pin and 6+2 pin

Vester

Well-Known Member
USA team member
A 6 pin PCIe connector for a video card is rated 75 watts maximum. A 6+2 pin connector is rated 150 watts maximum. The PCIe x16 slot is rated 75 watts.

I have some Radeon HD 7990 video cards that have two 6+2 connectors. Interestingly, there were two 6+2 to 6 pin adapters included with an MSI Radeon HD 7990 that I bought new. I tried to run the video card with those adapters and the mining rig locked up repeatedly until I removed that card from service. When I looked into the 6+2 connector on the adapter, only five of the six slots had pins. The missing pin is one of the positive (not ground) pins. Unknown wattage, but presume 75 instead of 150 watts.

Lesson learned: I had bought a generic, flat, supposedly for OCZ, 6+2 cable over a year ago to use on one of the video cards. I have chased problems with that video card for the whole time since installing it. When one of my original OCZ ZX cables failed this week, I compared the original and the replacement. The replacement cable only uses six pins, not 8! The problem was that the video card was under-powered. The card must have been running on the ragged edge of power limitation. It sporadically caused the computer to lockup. I have four new cables on the way and they have eight pins in both ends.
 
Last edited:

Vester

Well-Known Member
USA team member
I found two new cables on eBay and I found another source today, modDIY Home Page - PC Modding, Case Mods, Custom Cables.

I bought two EVGA cables and did the pinouts compared to the OCZ ZX cables. What a nightmare! I got the video card to run, but there were still problems and I shelved the two EVGA cables. I expect the eBay cables on Monday, 28 December.

FYI, I am a long-time user of PC Power and Cooling Products, which were bought by OCZ. OCZ sold out their memory business to Toshiba. The power supply busines is now owned by PC Power and Cooling. Their power supplies have three, 5 or 10 year warranties (Bronze, Gold or Platinum lines). I plan to stay with PC Power and Cooling.
 

Nick Name

Administrator
USA team member
I learned the hard way that cable pinouts for power supplies aren't the same, even from the same manufacturer. Luckily I didn't burn up anything expensive, just a cheap water pump. I have several cables around that I've lost track of which PSU they belong to.

I've heard good things in the past about PP&C although I've never used their products.
 

MetalGeek

New Member
USA team member
Yeah cables should be universal but :mad: they aren't. Most name brand power supplies are made by ODMs. Within a specific product series the different wattage units can be made by different manufacturers and can perform very differently. When I'm shopping I go to JonnyGuru and research what models are of quality at the needed wattage. That site is all things power supplies run by a Corsair power supply design engineer. He shows no brand loyalty when discussing the industry at large and all the site's recommendations run across all brands.
 

Vester

Well-Known Member
USA team member
I am still waiting for two cables that will work for the fourth video card. If they prove satisfactory, I will order another pair for the 5th video card. Hong Kong businesses closed a week for New Year celebrations. I should buy a set of wire connector terminal pin extractors and make my own cables from generic cables!
 
Top