1200W Thermaltake

[BullAnt]

Hey Guys, 

             First of all sorry if this has been asked in the past but I currently have an old 1200w Thermaltake PSU which is in perfect working order. It is powering my ATI 6900XT via 2 separate 8 Pin Pcie Cables, im looking at upgrading to a new 5080 which requires 3 x 8 Pin Pcie Cables. stupid me has thrown away a majority of my other spare cables, I’ve managed to locate  2 separate 6 Pin Pcie cables and I know I can get an adapter to convert it over to an 8 Pin, my question is should I connect the both the 6 Pin connectors to the same rail output on the psu or separate them. Ideally I love a 8 pin cable straight out of my psu but nobody offers them I even contacted Cablemod and gave them the pin configuration and photos of my original cable they offered no help. 

[PDifolco]

You only have 6 pin and no 6+2 ?

And they're originals coming with the PSU ?

[BullAnt]

26 minutes ago, PDifolco said:

You only have 6 pin and no 6+2 ?

And they're originals coming with the PSU ?

Yeah I’ve only got 2 Genuine 6 Pins cables spare as per this photo. 

[leclod]

I'd say you can't do that.

The 6 pin cables aren't made to support an 8 pin load.

Using one of your adapter might work but would be cheating and dangerous.

If you already tried to get thermaltake and third party cables without success I'd look for a new psu.

A decent psu can be not very expensive.

 

Edit : I finally got it. You want to convert two 6 pin cables into one 8 pin cable.

This should work, indeed.

How would you know how many rails and which header is which rail ?

You could just try out. If it works it works, if not try another configuration.

Edited August 5, 2025 by leclod

[Spotty]

1 hour ago, BullAnt said:

 First of all sorry if this has been asked in the past but I currently have an old 1200w Thermaltake PSU which is in perfect working order. It is powering my ATI 6900XT via 2 separate 8 Pin Pcie Cables, im looking at upgrading to a new 5080 which requires 3 x 8 Pin Pcie Cables.

That power supply is almost 20 years old. Buy a new ATX 3.x power supply with the 12+4 cable. If you can afford upgrading to an RTX 5080 you can afford a new power supply once every 20 years.

[BullAnt]

10 minutes ago, Spotty said:

That power supply is almost 20 years old. Buy a new ATX 3.x power supply with the 12+4 cable. If you can afford upgrading to an RTX 5080 you can afford a new power supply once every 20 years.

Yeah the things a beast I can’t kill it,it’s worked flawlessly over the time, I’ll upgrade when I build a new pc later on but it’ll be fine for a bit more time. 

[Spotty]

1 hour ago, BullAnt said:

I’ve managed to locate  2 separate 6 Pin Pcie cables and I know I can get an adapter to convert it over to an 8 Pin, my question is should I connect the both the 6 Pin connectors to the same rail output on the psu or separate them. Ideally I love a 8 pin cable straight out of my psu but nobody offers them I even contacted Cablemod and gave them the pin configuration and photos of my original cable they offered no help. 

Don't use a 6 pin to 8 pin adapter cable. You're already adapting PCIe to the 12V-2x6 connector. PSU > PCIe 6 pin > 6 to 8 adapter > 3x8pin to 12V2x6 adapter > GPU. That's a lot of connections. Each connector adds resistance and a potential failure point. You'd be better off just using a little bit of wire to bridge the +2 pins. If you have some spare cables with the +2 that you don't need you could even just cut the +2 bit off the cable and twist the two wires together. It's just sense pin to say that the PSU is a modern power supply that supports 8 pin PCIe and 150W... By "modern" I mean modern by 2007 standards. Looking at reviews for your unit it did support the new (at the time) PCIe 2.0 standard and the 8 pin PCIe connector, so it should be able to support the 150W over the PCIe cable. 

 

But... you absolutely should buy a new power supply.

[BullAnt]

20 minutes ago, Spotty said:

Don't use a 6 pin to 8 pin adapter cable. You're already adapting PCIe to the 12V-2x6 connector. PSU > PCIe 6 pin > 6 to 8 adapter > 3x8pin to 12V2x6 adapter > GPU. That's a lot of connections. Each connector adds resistance and a potential failure point. You'd be better off just using a little bit of wire to bridge the +2 pins. If you have some spare cables with the +2 that you don't need you could even just cut the +2 bit off the cable and twist the two wires together. It's just sense pin to say that the PSU is a modern power supply that supports 8 pin PCIe and 150W... By "modern" I mean modern by 2007 standards. Looking at reviews for your unit it did support the new (at the time) PCIe 2.0 standard and the 8 pin PCIe connector, so it should be able to support the 150W over the PCIe cable. 

 

But... you absolutely should buy a new power supply.

Yeah I hear exactly what your saying, it would indeed be a lot of added resistance due to the multiple connections. 

[BullAnt]

1 hour ago, Spotty said:

Don't use a 6 pin to 8 pin adapter cable. You're already adapting PCIe to the 12V-2x6 connector. PSU > PCIe 6 pin > 6 to 8 adapter > 3x8pin to 12V2x6 adapter > GPU. That's a lot of connections. Each connector adds resistance and a potential failure point. You'd be better off just using a little bit of wire to bridge the +2 pins. If you have some spare cables with the +2 that you don't need you could even just cut the +2 bit off the cable and twist the two wires together. It's just sense pin to say that the PSU is a modern power supply that supports 8 pin PCIe and 150W... By "modern" I mean modern by 2007 standards. Looking at reviews for your unit it did support the new (at the time) PCIe 2.0 standard and the 8 pin PCIe connector, so it should be able to support the 150W over the PCIe cable. 

 

But... you absolutely should buy a new power supply.

You’ll be happy lol I ordered a new PSU lol hopefully it’s good I just took a punt and ordered a ROG Strix 1200w Platinum, here’s to another 20 years lol