Anyone tryed 2 psu setup with add2psu?

[memory_leak]

Just a crazy thought I had since long: is it possible to combine to low-power (silent) PSUs into one bigger?

After some research on the webb, it seems that the idea has been already tested, and there seem to be different solutions on the market, most notably a connector called add2psu and a lian-li connector.

I found also a lot of posts on different forums varying form people using two psu setups successfuly, to those where people say this will innevitably fry whole system or at least one of PSUs. I just wonder if anyone has
experience with this kind of setup?

[edh]

I really really wouldn't. Power quality and efficiency will suffer badly.

Just how powerful is the system you are going to use?

[xan_user]

is it possible? yes.
but is it practical? that depends on what your goal is.

[memory_leak]

I have thoughts of getting two smaller fanless PSUs instead of one bigger. Seasonic 520W is enough for my needs, but I just wonder how abut 2x250 or 2x300, maybe there would be less stress on PSUs if work is divided between them, and thus less heat produced. It's just thoughts.

For the system it is going to be z170-deluxe, 6700K + Gtx990ti + some other minor stuff .

[edh]

I have thoughts of getting two smaller fanless PSUs instead of one bigger. Seasonic 520W is enough for my needs, but I just wonder how abut 2x250 or 2x300

Where are you hoping to get 250W or 300W passive PSUs from? Yes, there are obscure older passive PSUs (low efficiency) and industrial PSUs (expensive) but you will spend so much more doing this and the end result will be terrible in every single way. Just don't.

maybe there would be less stress on PSUs if work is divided between them, and thus less heat produced.

The Seasonic 520W is designed to run passively at 520W. It does it very well. A pair of 250W or 300W PSUs are designed to run passively at their designated power outputs. There is no benefit to be add. There are many dis-benefits however. Those two smaller PSUs are going to be less efficiency (name a sub 300W Platinum PSU?) so will actually produce MORE waste heat than the single PSU. Plus the power quality formed by doubling them together may give you many problems.

For the system it is going to be z170-deluxe, 6700K + Gtx990ti + some other minor stuff .

Not sure I see the point of fanless if you have a GTX 990Ti. The noise it makes will drown out any quiet fan cooled PSU anyway on load so a semi-passive PSU would equally make sense. The Seasonic Platinum 520W fanless is very good but I'm just saying that there may be other options that will be cheaper. Not too long to go until Pascal is launched so the 990 is not a good bet money wise.

I remember now a similar question was asked some time ago which sort of degenerated because the poster was absolutely set on the idea and wouldn't take no for an answer:
viewtopic.php?f=6&t=68093

To sum up, here are reasons NOT to do dual PSUs:
- Cost, 2 smaller PSUs will cost you more
- Efficiency, 2 smaller PSUs will be lower efficiency, you will use more power
- Heat output will be higher because of lower efficiency
- Power quality will be lower given two sets of ripple voltage
- Physical space required, you will either need one PSU external, do a mod or buy one of those dreadful double width cases intended for complete morons
- Reliability, they are not redundant, you have just doubled the probably of PSU failure by having 2 units
- Chance of damaging components? Unproven but under a fault condition you can't say what will happen
- Noise will be higher as two sets of components to buzz (or two fans spinning if fan cooled)
- Terrible mess of cables created to join 2 PSUs together and can you even get a modular PSU at 250-300W?

I hope I've persuaded you to forget the idea.

[memory_leak]

Sorry, there is no 990Tii (at least I don't know of), it is going to be 980gtx ti from evga which does turn off it's fans based on temp. Those times I game I will anyway game with headphones, but usually I am not gaming, so most of the time it will not be so hot. Furthermore I plan on running X on build in intel's gpu, and use GTX only with Windows via VM with pass-through for vga, so it will really be used relatively rarely. One might say a waste of money, but everyone has it's toys .

To be honest I haven't checked aviability of smaller PSUs. As said, it was thought. I wish makers did PSUs with this in mind, so one could buy and combine say 2x250 or 3x250 and or 2x300 or similar as the need arise. If they can make 500w fanless they could certainly make smaller ones too, with some dedicated circle to regulate sharing. The load does not need to be perfectly balanced, just enough to not stress any of those to go too hot. Just a x-mass wish .

[edh]

Sorry, there is no 990Tii (at least I don't know of)

OK, I only looked at what you'd written about wanting a GTX 990 Ti previously. The GTX 990 Ti has been fabled before but never launched and probably never will as Pascal is on the way, but as you had mentioned it previously, I assumed this some kind of theoretical system, not one you would build right now.

What are your intended games and at what resolution? Are you sure you need a GTX 980 Ti? It will make life far harder and while fans might be advertised as being off at idle, it doesn't always work that way - when you exit your game you are going to face a barrage of noise for the next 15 minutes until the core is back down to temperature.

I wish makers did PSUs with this in mind, so one could buy and combine say 2x250 or 3x250 and or 2x300 or similar as the need arise. If they can make 500w fanless they could certainly make smaller ones too, with some dedicated circle to regulate sharing. The load does not need to be perfectly balanced, just enough to not stress any of those to go too hot.

No, it makes no sense. Spreading thermal load would be a stupid argument to doing it. A higher powered PSU is DESIGNED to manage a higher thermal load than a lower powered PSU.

For pretty much any physical process doing it on a larger scale is more thermally efficient, cost efficient and more reliable. This is why Titanium PSUs are only available in high end models - take the same design and scale it down and it would be less efficient. Splitting the task down to two sets of hardware is entirely nonsensical.

There's wider precedents to doing this: How many cars do you know with 2 engines?!? Yes, there have been a few crackpot modified cars for publicity more than anything over the years but how many production cars?!? OK, there was the low production Cizeta-Moroder V16T but that's the only one I can think of fact fans:
https://en.wikipedia.org/wiki/Cizeta-Moroder_V16T

The only reason for multiplicity would be for redundancy (this is why aeroplanes have multiple engines to achieve required ETOPS ratings for flying over oceans) but you won't have this, it's going to be worse as there are 2 PSUs to fail and no system to manage redundancy. Server PSUs are available in a redundant configuration but they are not intended for silence at all and work on entirely different principles to chain them together.

Please give up on the idea.

[xan_user]

I doubt any 250 watt passive PSU would have enough actual 12v amperage to run any oc's gtx 9xxti (unicorns!).

Why do so many people want a fanless PSU, only to have it run a difficult too cool CPU and screaming GPU??!?!

[Behemot]

I'd go with 550W Corsair RMx/RMi or maybe EVGA G2 but those are told to have slightly noisier fan. All of them are semi-passive and will be more than enough for your needs.