Single rail vs multi rail

[VelikiPCguy]

Hey all, I'm a noob building my PC and I've found conflicting information about this online. Is a single rail PSU better / more stable than a multi rail PSU?

 

I was told the best PSU you could get right now is the Corsair AX1000X 1000W 80+ Titanium Modular, but I believe it's listed as single rail, even though multi rail is more modern technology.. so, what gives? Is single better than?

[8tg]

Depends on the hardware configuration more than anything. Multi rail units having multiple overcurrent sensors are more likely to fault out and prevent power delivery damage if you were to max one out, which is a useful feature for extremely high wattage systems.

Say you have multiple R9 295x2’s in a system, if one fails and starts drawing a ton of power on its individual 300w rail in a multi rail 1000w electrical system, it’ll cause the OCP to fault out and shut down. 
But if you have this setup on a single 1000w rail and one card starts drawing a ton of power, that individual 12v rail is going to let it go for a while before the wattage drawn triggers the OCP.

Thats the benefit, for high wattage systems, it’s better to have the fail safe trigger earlier and prevent further damage, versus having the single fail safe at a much higher threshold let a component overcurrent for too long, potentially causing damage to the rest of the system.

 

If you have a conventional build this isn’t a big deal, since most modern high power components have their own failsafes as well, and modern power supplies even with high wattage single rails can detect when an overcurrent is happening even before hitting the OCP trigger threshold.

But if you’re running multiple 300w+ graphics cards, and they’re older models like 980ti lightnings or multiple Titan Z’s or something, you’d want multi rail just in case a card fails and causes an OCP, a multi rail OCP will trigger earlier and prevent most damage.

[VelikiPCguy]

6 minutes ago, 8tg said:

Depends on the hardware configuration more than anything. Multi rail units having multiple overcurrent sensors are more likely to fault out and prevent power delivery damage if you were to max one out, which is a useful feature for extremely high wattage systems.

Say you have multiple R9 295x2’s in a system, if one fails and starts drawing a ton of power on its individual 300w rail in a multi rail 1000w electrical system, it’ll cause the OCP to fault out and shut down. 
But if you have this setup on a single 1000w rail and one card starts drawing a ton of power, that individual 12v rail is going to let it go for a while before the wattage drawn triggers the OCP.

Thats the benefit, for high wattage systems, it’s better to have the fail safe trigger earlier and prevent further damage, versus having the single fail safe at a much higher threshold let a component overcurrent for too long, potentially causing damage to the rest of the system.

 

If you have a conventional build this isn’t a big deal, since most modern high power components have their own failsafes as well, and modern power supplies even with high wattage single rails can detect when an overcurrent is happening even before hitting the OCP trigger threshold.

But if you’re running multiple 300w+ graphics cards, and they’re older models like 980ti lightnings or multiple Titan Z’s or something, you’d want multi rail just in case a card fails and causes an OCP, a multi rail OCP will trigger earlier and prevent most damage.

Ah I see, thank you. I'm thinking of running an EVGA RTX 3090 Kingpin, and with my whole build, PC Part Picker is saying it should eat up between 600 - 700w. So then it shouldn't be an issue in that set-up if the 1000w PSU is only single rail, even though multi rail is technically safer?

[seon123]

32 minutes ago, NewwGuyy123 said:

Is a single rail PSU better / more stable than a multi rail PSU?

No. "Single rail" is just a nice way of saying that they cheaped out by omitting multi rail OCP. Not having multi rail OCP on a 1000W PSU would e.g. allow it to pull 1000W through a single SATA connector. Which you would obviously not want.

 

A type of failure that would be caught by multi rail OCP is rare, so you could argue that it's not needed. But you could say the same about any other protection as well.

26 minutes ago, NewwGuyy123 said:

I was told the best PSU you could get right now is the Corsair AX1000X 1000W 80+ Titanium Modular,

Whoever told you that... is just wrong. I recommend you stay away from their "advice".

26 minutes ago, NewwGuyy123 said:

but I believe it's listed as single rail, even though multi rail is more modern technology

It's not more modern, both have existed for ages.

24 minutes ago, 8tg said:

modern power supplies even with high wattage single rails can detect when an overcurrent is happening even before hitting the OCP trigger threshold.

What protection would trigger on a single rail PSU, if it's not drawing enough to trigger OCP?

[VelikiPCguy]

2 minutes ago, seon123 said:

Whoever told you that... is just wrong. I recommend you stay away from their "advice".

So if you were getting a great, 1000w multi rail PSU, which one is top of the market atm?

[seon123]

Just now, NewwGuyy123 said:

So if you were getting a great, 1000w multi rail PSU, which one is top of the market atm?

Where are you buying from? The pricing will vary, and so will any recommendations. If you just want the best PSU, regardless of price, just get the AX1600i.

[VelikiPCguy]

4 minutes ago, seon123 said:

Where are you buying from? The pricing will vary, and so will any recommendations. If you just want the best PSU, regardless of price, just get the AX1600i.

I'm not looking to save on the PC but I also wouldn't want to splurge entirely unnecessarily, and I've read that even a 1000w PSu is overkill (let alone 1600w). Is there a 1000w version that's better than the AX1000X one?

[seon123]

13 minutes ago, NewwGuyy123 said:

I'm not looking to save on the PC but I also wouldn't want to splurge entirely unnecessarily, and I've read that even a 1000w PSu is overkill (let alone 1600w). Is there a 1000w version that's better than the AX1000X one?

Again. Any meaningful recommendations will depend on the pricing, which depends on where you're buying from. If pricing does not matter, just get the AX1600i.

[VelikiPCguy]

37 minutes ago, seon123 said:

Again. Any meaningful recommendations will depend on the pricing, which depends on where you're buying from. If pricing does not matter, just get the AX1600i.

Well let's say in the 400-500 USD range, since the AX1000 is around 300 USD adn the AX1600i is around 700.

[Spotty]

1 hour ago, NewwGuyy123 said:

So if you were getting a great, 1000w multi rail PSU, which one is top of the market atm?

Either the Corsair HXi/HX or the be quiet Dark Power Pro 12

[VelikiPCguy]

9 minutes ago, Spotty said:

Either the Corsair HXi/HX or the be quiet Dark Power Pro 12

Isn't the HX/HXi just a worse version of the AX? is Dark Power Pro 12 better than that?

[seon123]

1 hour ago, NewwGuyy123 said:

Well let's say in the 400-500 USD range, since the AX1000 is around 300 USD adn the AX1600i is around 700.

Damn, the 1000W PSU market sucks right now... The HX1000, which should normally be around $200 is up to near $400. As Spotty suggested, the Dark Power Pro 12 1200W is an option. It's still in stock on Amazon for $400, which, from what I could find, looks like the normal price for it. So might as well go for that one.

13 minutes ago, NewwGuyy123 said:

Isn't the HX/HXi just a worse version of the AX? is Dark Power Pro 12 better than that?

No, they are completely different, and the HX/HXi is better. The HX and HXi are mostly the same, the HXi just has software monitoring. They have multi rail OCP, they are quieter, they use decent fans, they are made by a larger OEM etc.

 

Do note however that the AX and AXi are also completely different.

[GoldenLag]

4 hours ago, NewwGuyy123 said:

Isn't the HX/HXi just a worse version of the AX?

nope, completely different OEM etc etc etc. 

 

better units than the AX. and they are fairly similar to eachother

 

the AXi is completely different to the AX. AXi being a fully digital, with digital monitoring PSU made by Flextronics. and the AX being a Prime Titanium from Seasonic. 

 

tl;dr: the AX is not very appealing compared to the cheaper HX and HXi, or the more expencive AXi. The AXi being the best consumer available PSU on the market

4 hours ago, NewwGuyy123 said:

is Dark Power Pro 12 better than that?

DPP12 is in the afaik in the top 3 of current powersupplies sold on the market. Its a digital powersupplies but it lacks some things that make it inferior and cheaper than the AXi. if you want to spend 500$ on a PSU and the AXi isnt in that range, a step down would be the DPP12. 

 

granted the HX and HXi are both great powersupplies, and there arent a ton of reasons to spend more than the typical asking price for those on a PSU. 

 

6 hours ago, NewwGuyy123 said:

I was told the best PSU you could get right now is the Corsair AX1000X 1000W 80+ Titanium Modular

idk who told you this, but there are far better units on the market. i assume you meant the AX1000. afaik there isnt a unit called AX1000X. 

 

the AX is a good unit as far as singlerail units go. if it was available in a 650w variant it would make sense, but at 1000w you want to have multirail. 

[boghubodaghi]

5 hours ago, seon123 said:

they are made by a larger OEM

What does that do?

[VelikiPCguy]

On 5/6/2021 at 5:10 AM, seon123 said:

No, they are completely different, and the HX/HXi is better. The HX and HXi are mostly the same, the HXi just has software monitoring. They have multi rail OCP, they are quieter, they use decent fans, they are made by a larger OEM etc.

 

Do note however that the AX and AXi are also completely different.

So between the HX, HXi, AX, and AXi, which one would you recommend going for?

[VelikiPCguy]

On 5/6/2021 at 9:20 AM, GoldenLag said:

The AXi being the best consumer available PSU on the market

Just to be clear, when you say AXi you mean the Corsair AX1600i, correct? And there isn't a 1000w version of that?

[IIIIIIIIII]

9 minutes ago, NewwGuyy123 said:

Just to be clear, when you say AXi you mean the Corsair AX1600i, correct? And there isn't a 1000w version of that?

Yes. The only AXi that is currently on the market is AX1600i. HXi is the best. If you are not interested in monitoring, choose HX.

[VelikiPCguy]

8 minutes ago, IIIIIIIIII said:

Yes. The only AXi that is currently on the market is AX1600i. HXi is the best. If you are not interested in monitoring, choose HX.

So then AXi > HXi > HX > AX?

[IIIIIIIIII]

17 minutes ago, NewwGuyy123 said:

So then AXi > HXi > HX > AX?

Yes. HXi and HX are the same except for iCUE.

Edited May 8, 2021 by IIIIIIIIII

[VelikiPCguy]

Just now, IIIIIIIIII said:

Yes.

And where does the DDP fit into that, is it better than HXi?

[IIIIIIIIII]

14 minutes ago, NewwGuyy123 said:

And where does the DDP fit into that, is it better than HXi?

What is DPP? Bequiet Dark Power PRO 12? It uses a better design than the HXi, but has no monitoring capabilities.

Edited May 8, 2021 by IIIIIIIIII

[GoldenLag]

7 hours ago, NewwGuyy123 said:

And where does the DDP fit into that, is it better than HXi?

AXi>DPP12>HXi>HX>AX 

 

DPP12 is in the top 3-ish of powersupplies, not sure if the HXi scratches top 8

Edited May 8, 2021 by GoldenLag

[VelikiPCguy]

12 hours ago, GoldenLag said:

AXi>DPP12>HXi>HX>AX 

 

DPP12 is in the top 3-ish of powersupplies, not sure if the HXi scratches top 8

 

17 hours ago, IIIIIIIIII said:

What is DPP? Bequiet Dark Power PRO 12? It uses a better design than the HXi, but has no monitoring capabilities.

Perfect, thank you!

[Guest]

On 5/5/2021 at 6:20 PM, NewwGuyy123 said:

I was told the best PSU you could get right now is the Corsair AX1000X 1000W 80+ Titanium Modular

Not sure who told you that.

 

AX1600i is the best PSU you can get right now.  But that's overkill.

 

Arguably, the HX and HXi are better than the AX.  The AX is just "more efficient" (Titanium vs. Platinum).

[Guest]

On 5/8/2021 at 3:31 AM, GoldenLag said:

AXi>DPP12>HXi>HX>AX 

 

DPP12 is in the top 3-ish of powersupplies, not sure if the HXi scratches top 8

Damn.  That's cold.  HX/HXi is one of my all time favorite PSUs.  And I wasn't even part of bringing it to fruition!

 

What do you base your opinion on?