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Dual Power Supplies, Good, Bad, or Ugly


ksquared

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Background, I have the working computer with the SF450, working fine with the 1660 Super GPU.

 

I'm wanting to replace the 1660 Super with the 3080 or 3090. Obviously a major difference. Obviously the SF450 isn't going to power that.

 

So, instead of what I see as wasting the SF450 and removing it, to purchase a very large power supply, is it possible to use another SF450 specifically to power the GPU? I know there are potential issues if not done properly, so I'm not going to do anything without learning from the experts here.

 

It seems that people have done dual power supplies, and the PC-011 has space for dual power supplies, so if it isn't possible to do why does the case have two spaces?

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Back in the day, when graphics cards with PCIe connectors first came out, but not all PSUs had PCIe connectors... never mind enough power... dual PSUs were VERY common.

 

FSP Booster X3: https://www.techradar.com/reviews/pc-mac/pc-components/cases-cooling/power-supplies/fsp-booster-x3-39494/review

 

TT Power Express: https://www.cnet.com/products/thermaltake-toughpower-power-express-w0157-video-card-power-supply-450-watt/

 

Ultra Power Partner: https://www.overclockersclub.com/reviews/ultra_power_partner/

 

The trick is really getting both PSUs to power up at the same time.

 

I've used "fog light" relays: http://jongerow.com/PSU_relay/index.html

 

But you can actually buy devices that do the same thing: https://www.amazon.com/PSU-Supply-24-Pin-Motherboard-Adapter/dp/B072JM7KVD

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Thanks for the information.

 

I'm not sure why this is so frowned upon though. I understand if you're doing the paperclip method it isn't safe, but with something properly wired it seems that it should be fine.

 

The one mentioned, TT Power Express, seemed to be specifically made for powering a graphics card.

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Thanks for the information.

 

I'm not sure why this is so frowned upon though.

 

It is? By who?

 

The one mentioned, TT Power Express, seemed to be specifically made for powering a graphics card.

 

They ALL are made specifically for powering graphics cards.

 

And there were other models out there at the time as well. But these things were from about 10+ years ago.

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Maybe the PSU manufacturers frown upon it??

 

Long ago it was keep it working, use ingenuity to make it work. Now, just replace with something bigger.

 

I see why the oddly shaped PSUs, such as the TT W0157 which fit into a 5.25" drive bay, didn't catch on, as they were expensive niche products. But when the case can fit two ordinary PSUs, it seems to be a viable alternative.

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I see why the oddly shaped PSUs, such as the TT W0157 which fit into a 5.25" drive bay, didn't catch on, as they were expensive niche products. But when the case can fit two ordinary PSUs, it seems to be a viable alternative.

 

Again, we're talking about over 10 years ago. They weren't expensive for the time. And it wasn't niche as every case on the market had a minimum two 5.25" bays. And there were no cases made at that time that could use two "normal" PSUs.

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Again, we're talking about over 10 years ago.

 

That's what I wonder about though.

 

As the power requirements have gone higher and higher, I would think dual power supplies would be more common. Not for somebody building a computer with all new components, but somebody upgrading as seems common with the video cards. But maybe as mentioned, not enough cases will accomodate it, and now the 5.25" drive is extinct too.

 

So with something such as add2psu, it should be doable and safe? Somewhat another incentive at the moment is some of the larger power supplies are out of stock, yet the smaller ones are available.

 

I'll add, interesting reading on the website and the "fog light relay." I'll say I really like the SF versions, but I really object that there isn't an option to specify regular length cables. In my opinion, this is greatly holding back the SF popularity.

Edited by ksquared
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I'll say I really like the SF versions, but I really object that there isn't an option to specify regular length cables. In my opinion, this is greatly holding back the SF popularity.

 

Well, it's an SFX PSU made for SFX builds. So it comes with SFX length cables. I use the SF600 myself and it's in a Fractal Meshify C. Since after market cables are readily available, I was able to get the replacement 8-pin I needed for the motherboard. Fortunately, the 24-pin and PCIe cables were long enough.

 

Funny though... I actually had to buy one fan cable extender. LOL! Never had to do that before.

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Well, it's an SFX PSU made for SFX builds. So it comes with SFX length cables. ... Since after market cables are readily available ...

 

That's where I think it is being limited. It is an SFX sized PSU, but it is a spectacular PSU of any physical size, but especially the 450W version where quality is often lacking in other brands.

 

And yes, there are after-market cables, an excellent set is the Corsair 8920228. But then the economic reality is that for a set of very nice looking wires you're paying essentially the price of an SF450 power supply, a legitimate, complex, well-engineered piece of electronic equipment that powers a computer.

 

The help from jonnyguru has been greatly appreciated!

 

So ulitmately I decided at best it was ugly, and possibly bad.

 

I studied the W0157 Graphics Card PSU, and maybe I don't understand something. It seems there is a rule, never ever power the same item from two different PSUs. That seems straightforward, and easy to do for a hard drive or CD. But unless I'm not understanding, I thought the graphics card got power from the PCI-e connectors and the motherboard. So if the one PSU is powering the motherboard, and the other PSU is powering the PCI-e connectors, that seems to be a potential problem to a non-expert such as myself. One other bit of interesting potential problems too is that I guess it is possible to plug each PSU into a different outlet and thus on a different leg of the 120V power from the electric company. I guess that could be avoided of course.

 

My first choice would have been another SF450. If Corsair made a legitimate setup using quality components in order to power the graphics card with a dedicated PSU, I would have done that and been happy for years.

 

So instead, I wanted the Corsair HX1000, another very high quality PSU, unfortunately not in stock here, but available at Newegg for a 61% price gouge ($344 from Tom & Jerry through Newegg vs $205), of course that isn't going to happen. The HX1000i was actually $14 less at $330 from BuyOnline through Newegg, actually just a 16% markup over the $285 price from Corsair. The alternative, Corsair RM1000i, again not in stock here. But I could get it on Newegg, for a 50% price gouge ($300 from BuyOnline through Newegg vs $200). That isn't going to happen either.

 

The end result is I bought a non-Corsair PSU. That hasn't happened in a LONG time.

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I studied the W0157 Graphics Card PSU, and maybe I don't understand something. It seems there is a rule, never ever power the same item from two different PSUs.

 

How did you come to that conclusion?

 

With multiple cables and power through the slot even using THE SAME PSU, resistance due to cable length, trace length, etc. is going to vary a good deal, even coming from the same PSU.

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Somewhere I read that it had the potential to not be matched in phase between the two different PSUs.

 

Here is one reference to the potential problems (but back in 2014): https://forums.tomshardware.com/threads/dangers-of-dual-psu.1992711/

 

But yes, Thermaltake did use the W0157 only attached to the graphics card.

Edited by ksquared
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Somewhere I read that it had the potential to not be matched in phase between the two different PSUs.

 

Here is one reference to the potential problems (but back in 2014): https://forums.tomshardware.com/threads/dangers-of-dual-psu.1992711/

 

But yes, Thermaltake did use the W0157 only attached to the graphics card.

 

Opinion of random user on a forum.

 

The power through the PCIe slot is not completely isolated from the power coming in through the PCIe power connectors.

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Opinion of random user on a forum.

 

The power through the PCIe slot is not completely isolated from the power coming in through the PCIe power connectors.

 

Yes, I completely agree. The problem is I'm not an expert, that random user obviously isn't an expert, and all would agree that jonnyguru is an expert.

 

The problem thus is back to what I initially focused on, there is no legitimate kit, designed by experts, with the high quality of Corsair, out there for a non-expert like me to just buy and connect with 100% certainty.

 

I don't see Corsair selling 100K such kits, but IMHO a profit on even 1000 kits would be worth something. It would have been down to 999 if I had the chance to purchase one at an economically feasible price.

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Yes, I completely agree. The problem is I'm not an expert, that random user obviously isn't an expert, and all would agree that jonnyguru is an expert.

 

The problem thus is back to what I initially focused on, there is no legitimate kit, designed by experts, with the high quality of Corsair, out there for a non-expert like me to just buy and connect with 100% certainty.

 

I don't see Corsair selling 100K such kits, but IMHO a profit on even 1000 kits would be worth something. It would have been down to 999 if I had the chance to purchase one at an economically feasible price.

 

Corsair has one case that supports two PSUs and it also supports two motherboards. Wanting/needing two PSUs is a niche of a niche. It's not something a big company like Corsair is going to see an ROI with if selling only 1000 pieces a year.

 

Anyway... Phanteks (experts, but on a smaller scale than Corsair) does have a device for running two PSUs to one system: http://www.phanteks.com/PH-PWCOB.html

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