why do power supplies bigger than 550W exist?

[kiwibacon]

so i checked the power usage at the wall on my system.

2 Monitors

3800x

2080ti overclocked

fibre box

router

 

in a gaming session

 

450W @ the wall 

 

wtf am i doing with a 750 W PSU

[Guest]

Most systems are completely fine with a 500-600W PSU. But sometimes you need more power like if you're doing SLI or heavy overclocking (a 9900k at 5.1Ghz can draw up to 250W) or the Intel HEDT lineup, those CPUs also draw a lot of power when overclocked. Also some graphic cards like Vega64 can still draw over 300W.

But most of the time if you have a normal setup like a 2600 and a 1660ti or a 1080, you don't need more than 500W

[aaradorn]

Protecting yourself from certain situations, people with beefier systems need bigger power supplies, upgrade ability, Power supplies are pretty inexpensive these days so going bigger barely costs more. 

[keskparane]

dunno. why did you buy a 750?

[Bishop Crane]

For systems that need more than 550W ?

Seriously though, there are plenty of workstation class machines that have dual CPU's each of which have a TDP in excess of 200W and they're running workloads which use ALL of the machine.  You add a decent GPU to that and you're easily past the 550 mark.

Or you add a second GPU to your existing machine, and easily pass the 550W also.

[Stormseeker9]

29 minutes ago, kiwibacon said:

so i checked the power usage at the wall on my system.

2 Monitors

3800x

2080ti overclocked

fibre box

router

 

in a gaming session

 

450W @ the wall 

 

wtf am i doing with a 750 W PSU

What model psu do you have ...?

[TrigrH]

58 minutes ago, kiwibacon said:

so i checked the power usage at the wall on my system.

2 Monitors

3800x

2080ti overclocked

fibre box

router

 

in a gaming session

 

450W @ the wall 

 

wtf am i doing with a 750 W PSU

Because load power consumption is not the same as peak power. A 550w psu would run your system most of the time but I wouldn't be surprised if it shut off from time to time.

[Cypher-Jackson]

Because SLI/Crossfire was a thing at some point

Because consumers think more is better 

Because workstations exist

Because the maximum efficiency is at about 50% power usage

 

[OrionFOTL]

43 minutes ago, Cypher-Jackson said:

Because the maximum efficiency is at about 50% power usage

Your other points are valid, but this one isn't a reason to buy oversized PSUs. If you buy a bigger power supply to have 2% higher efficiency (2% higher at half load versus 2% lower at full load), you spent $30-$100 more to save $2-5 per year.

[hello_there_123]

Most consumers think like cavemen. Higher is better obviously

[PianoPlayer88Key]

On 7/17/2019 at 11:43 AM, OrionFOTL said:

Your other points are valid, but this one isn't a reason to buy oversized PSUs. If you buy a bigger power supply to have 2% higher efficiency (2% higher at half load versus 2% lower at full load), you spent $30-$100 more to save $2-5 per year.

In that case, would it be better to just get a lower-wattage PSU with a higher 80+ rating that's the same or higher on the tier list? (For example, like a 550W 80+ Platinum instead of 850W 80+ Gold)

[Spotty]

28 minutes ago, PianoPlayer88Key said:

In that case, would it be better to just get a lower-wattage PSU with a higher 80+ rating that's the same or higher on the tier list? (For example, like a 550W 80+ Platinum instead of 850W 80+ Gold)

Probably. Really depends on by what metric you're measuring, and what system you're using it in.
If it's a system that requires less than 550W, then yes, a better quality and more efficient power supply would be better than a lower quality, less efficient power supply that has a higher wattage that you do not require.

If you're talking about a multi-GPU set up that draws more than 550W you would obviously choose the 850W 80+ Gold unit in that scenario.

 

The "PSUs are most efficient at 50%" is a myth. On a modern, quality PSUs the difference in efficiency between 30%, 50%, and 80% loads may only vary by <1%. It's entirely a non-issue.

[Mick Naughty]

Because more is better. 

[Mr.Humble]

Because you might have a PSU with semi-passive cooling, meaning the fan turns off if you're under certain load. Get a big enough PSU and you effectively have a passive unit, often for lower price than an actual fully passive PSU, and you have plenty of upgrade options.

 

At least that's why I got a bigger unit then my PC would need.

[Fasauceome]

A 32 core threadripper and a 2080 ti sure would love a PSU bigger than 550 watts that's for sure.

[seon123]

2 hours ago, Mr.Humble said:

Because you might have a PSU with semi-passive cooling, meaning the fan turns off if you're under certain load. Get a big enough PSU and you effectively have a passive unit, often for lower price than an actual fully passive PSU, and you have plenty of upgrade options.

 

At least that's why I got a bigger unit then my PC would need.

Then why does the EVGA G3 1000W exist? It has a semi passive mode, but runs the fan at over 1500RPM at a 60W load. And what about PSUs that don't have semi passive modes?

If someone wants to get a quiet PSU, they should get a quiet PSU, not a high wattage one. 

8 hours ago, PianoPlayer88Key said:

In that case, would it be better to just get a lower-wattage PSU with a higher 80+ rating that's the same or higher on the tier list? (For example, like a 550W 80+ Platinum instead of 850W 80+ Gold)

It would be better to ignore the efficiency, and just read reviews to find the overall better PSU. 

 

On 7/17/2019 at 5:04 PM, aaradorn said:

Protecting yourself from certain situations, people with beefier systems need bigger power supplies, upgrade ability, Power supplies are pretty inexpensive these days so going bigger barely costs more. 

By that logic, why not get a 7640X and an X299 board? You get that upgradability, even though you pay more, and get a worse CPU. That's just stupid. If you have more money to spend on a PSU, get a better one, not a higher wattage one. 

[Princess Luna]

9 minutes ago, seon123 said:

It would be better to ignore the efficiency, and just read reviews to find the overall better PSU. 

True enough even though if you really aiming for a 80+ Platinum or god forbid a 80+ Titanium the odds you'll end up with a bad unit are near zero... at most you could have got something better for the money but not a bad one...

 

We understand 80+ is not a measure of unit quality/reliability but when you're genuinely considering those two last tiers it's at least really hard to go wrong.

[OrionFOTL]

2 hours ago, Mr.Humble said:

Because you might have a PSU with semi-passive cooling, meaning the fan turns off if you're under certain load. Get a big enough PSU and you effectively have a passive unit, often for lower price than an actual fully passive PSU, and you have plenty of upgrade options.

 

2 hours ago, Mr.Humble said:

At least that's why I got a bigger unit then my PC would need.

...... Your PSU doesn't have a semi passive mode. 

[Mr.Humble]

4 hours ago, OrionFOTL said:

 

...... Your PSU doesn't have a semi passive mode. 

[TrainFan475]

I bought a 650 watt psu just so I won't be kicking myself later when I upgrade my gpu (a gtx 1050 at the moment).