[SOLVED] PSU - Cable interchangability

[Matt1155]

Hiya,

Planning on installing a new GPU (KFA2 3080ti HOF), upgrading from old Palit 1070. The new GPU needs 3 x 8-pin connectors.

Haven't done an upgrade this big before and currently use an RM750x. I believe this model has four 8-pin connectors (so one for the CPU which is only a 3700X so not a big power draw, and three for the GPU should work I think?)

However, the RM750x has been provided with only two PCIe cables, which makes this difficult!

I was recently working on another computer and bought a TX750M, for which I still have the cable set.

So, a few questions:

1. Could I use a PCIe cable from the TX750 PSU for my RTX3080Ti? This link: https://www.corsair.com/fr/fr/psu-cable-compatibility suggests that it would work? But I am a tad confused re. Type 3 and Type 4 cables (what's the difference? Does it matter? Something to look out for that I could do wrong?

2. If I shouldn't interchange between the two, what cable would you recommend I use instead? Is there somewhere reliable where I can buy a suitable cable online?

3. All things above considered, is it worth me just paying someone £40 to deal with the problem rather than tackle it myself? Would Currys, for example, be able to do the installation and supply a suitable additional cable? (difficult one I know as some of these big stores seem to have questionably knowledgeable technicians - I have done PSU replacement a couple of times before so have a general idea of what I'm doing but never for 3 x 8-pin cables!)

Thanks for any advice in advance!

Also feel free to tell me if I'm being an idiot...

 

[Eximo]

Cablemod sells a wide range of cables for Corsair power supplies, definitely try there. They also resell through Amazon and other PC parts retailers, so what they might not have in their store can be found elsewhere. I bought a white cable kit from them some time ago for my RM850x.

A nice way to get them all to match, and avoid the bulky daisy chained cables, or the sometimes awkward flat ribbon style cables.

That said, you are likely to not actually have enough to run your 3080Ti under all conditions. These cards are known for their very high power spikes which can cause OCP to kick in on even the RM850x.

According to that chart, yes, your cables should be interchangeable between those two power supplies. I would do a visual double check myself or test it with a multimeter.

 

[Matt1155]

Hi Eximo,

Thanks for your response!

Regarding your point on the high power spikes - it's a difficult one... I see plenty of people saying that the newer cards can cause high power spikes but also some people also saying that 750W is more than enough!

Worst comes to the worst, I could always go for a 1000W PSU if needed (although that'd be a tad expensive!)

Not planning on going nuts with OC'ing so hopefully won't trip OCP but, as you said, heard some worrying info about it that may cause problems!

Thanks again.

 

[Eximo]

It wasn't particularly gaming that caused it, though if you ran 4K native or something ,might do it. There were references on Corsair's forums to 3090 popping RM850x doing deep learning. But dropping down another 100W, questionable.

Most people are going with the traditional total wattage based on the TBP of the cards, but it has been shown that sudden spikes from the card are much larger. Sensitive OCP, which is kind of a good thing, are easily tripped up. RMx supplies are pretty good though, seems like they survive just fine, just be prepared for unexpected shutdowns.

 

[Matt1155]

OK, thanks, will keep an eye on it!

 

[Vic 40]

What cpu?

 

[Matt1155]

Ryzen 3700x

Other stuff:

Fractal S36+ Prisma (3 x 120mm argb fans)
2 x 200mm argb front fans
1 x 120mm exhaust fan
2 x monitors (1440p)
1 x nvme 500GB SSD
ASUS ROG Strix x570 motherboard
16GB RAM (3600Mhz)

A few other peripherals + extras (mouse, keyboard, external HDD, external SSD) etc.

but CPU shouldn't be too power hungry?

 

[Vic 40]

Ryzen 3700x



but CPU shouldn't be too power hungry?

No not really. Think you're fine, but keep an eye out for symptoms as said above.