Is using molex to 6 pin safe?

[ioskyx768]

I have a hd 7770 ghz but a generic brand 420w thermal master psu without any 6 pin connectors (23A total amperage on 2 rails) Would it be safe to use 2 molex to single 6 pin pcie adapter?

 

[Nikola Aslanov-1338074]

7770 can get almost all power through the pcie slot. Pci-e slot supplies up to 75W. 7770 needs ~80, so it gets very little from the 6pin. Using converter cables is perfectly safe in this case. You can even use single molex to 6 pin.

 

[MrVic87]

Does this apply with a gtx 760? Evga supplied a 6 pin with 2 molex ends.

 

[Nikola Aslanov-1338074]

760 uses significantly more power than 7770. The whole thing depends on the PSU amperage and wattage but generally I'd say that.
760 will probably work OK with 1x6 pin generic PCIe connector + 1x dual molex to 6 pin.
Most decent & recent PSUs 500+ watts have 2xPCIE 6 or 6+2 pins. I would not risk a $300 video with cheap PSU.

 

[MrVic87]

Nikola, this is where I'm struggling now. The psu I currently have is a evga bronze 600b psu. It only have 1 PCI 6+2 pin. I connected that to the 8 pin slot, and used the 6 pin with molex end (provided with the card) connected to the molex cable from psu. I am getting the impression that the psu isn't powerful enough for that card

 

[Nikola Aslanov-1338074]

Recommendations for 760 (Evga model) are "500 watt or greater power supply with a minimum of 30 amps on the +12 volt rail". 600W evga PSU will work fine. (I saw it is 49A at 12V)
The average power figures are:
75W for PCIE x16 slot.
75W for PCIE 6pin cable.
Up to 150W for 8 pin PCI-E (6+2 probably qualifies as such) but I'm not sure that all PSUs support this correctly.
40W for molex.
760 uses ~170W at load - so it will work fine with slot + 6 or 8 pin + molex. It theoretically SHOULD work with Slot + 8pin, but if there is a 6pin slot - lets use it.

 

[MrVic87]

Nikola that's great to know. I just don't know why I can't get a BIOS or anything to show on my monitor or hdtv. I figured to have made the right connections but I can't seem to get it to work at all.

I didn't mean to hijack the OP thread.