VGA Molex Power Connector - can I use it with Molex - PCI-E Power Adapter

Struggling to get my 480 SOC working at full clock speeds and I'm suspecting PSU - I think I had some minor improvement by going from using both PCI-E power 6 pins from my PSU (one plugged into a 8 pin PCI-E power adapter) to using one of the PCI-E power cables into the 8 pin adapter, and then using 2xMolex HDD connectors into a converter for PCI-E 6 pin power

reason for doing this was as the 2 PCI-E 6 pins are on the same rail on my PSU

I found this evening another power cord from PSU - a 4 pin Molex but with thick dedicated cable to PSU - I think its a VGA 4 pin Molex connector - legacy thing

can I use this as one of the feeds into the 2 Molex - PCI-E power adapter I have ?

at moment the 2 Molexs I'm using are off the same cable off PSU - can't use off seperate branches as the other 2 branches are SATA only

any ideas please

What PSU do you have, and what CPU (and OC) as well?

hi there - its a Tagan 700W Dual-engine - its about 4 years old

it ran a 570 and 4890 fine - and the GTX480 works fine at around stock speeds, but not at the out of the box OC speeds. I sent it back to the manufacturer as suspected faulty, and they tested it NFF - so only thing remaining is my PSU - I haven't found my volt meter yet to test if any droop on 12V rail

the Tagan has 4x 20A 12V rails, with the PCI-E 6 pins off 12V3

CPU is a Q6600 oc'd to 3.5 gig (at 1.5 VCore) - but tried it at stock/stock volts and had no bearing on the GPU (I thought it may drop power load on PSU a bit)

at idle I'm seeing 190W drawn from wall (with a wall meter) - and under load in games around 420W, in OCCT (where the GPU is failing) - I'm seeing around 490-500W draw

My bet is that you need a new PSU, 4 years is a long time in PSUland. I don't know how Tagan is as a brand.