[SOLVED] Is using upto almost 90-100% of the power supply limit ok?

May 17, 2020
5
0
10
0
Hi,
I have an all-in-one PC and am stuck with a 220W power supply due to the small form factor of my PC. I'm thinking of upgrading my CPU that currently has a TDP of 65Ws to one with 95W. I have a wattage meter and the average usage currently is about 100W but when gaming it stays around 150-175W during normal gameplay and reached a maximum of 185W. With the new CPU it will possibly reach 215W max or a bit higher (PSU is 220W so it may be awfully close to the limit). Do you guys think the upgrade would be safe or could it lead to problems like dead components since the PSU may sometimes reach almost 100% and will be running around 90% when gaming? I can't do anything about the PSU, I just wanna know if the CPU upgrade (+30watt TDP) would be beneficial (or disastrous) since I currently have a CPU bottleneck. Trying to go from an i5-2400S to i5 2500 (i know it's still rubish but I'm limited by an old motherboard and an all-in-one pc that's very hard to upgrade).

This is the PSU if that's of any help: Caddy 33.3CN05.XXX
Thanks.
 
Last edited:
I see, thanks for the advice. My PC is a bit old so the power supply probaby has aged. But the supply will only use around 80% of what my AC wattage meter says from what I've learnt about efficiency, so I calculate it will only have a max load of 78% and will normally run around 55-75% while gaming. Is it still risky in your opinion I'm not too sure myself?
I would say you are really pushing your limits. You could try it. But unexplained performance drops, system crashes, or shutdowns are a sign you pushed the PSU beyond it's limits.

To answer your question, the PSU wattage rating is the DC output side (As JonnyGuru stated) But not everybody list the output the same way. The good brands use the 12V output wattage as the power rating. While the cheap brands may add in the 3.3V, 5V, and 12V together to get a wattage output. So a cheap power supply may have like 10 Watts on the 3.3V, 25 Watts on the 5V, and 165W on the 12V and call that 200 Watts (10 + 25 + 165) Some cheap brands even list wattage with "peak" or "max" in the wattage phrasing indicating that they aren't meant to hold that power for more than a few ms.

A good power supply review will always do a torture test, where they run it at full power load for 5->10 minutes, and run it at 80% power load for a good 8->24hours.

I'm not sure but does this look like your power supply?

https://www.atxpowersupplies.com/powersupplies/Acer-Aspire-Z5761-power-supply-replacement.php
 
Reactions: Bazookatron263
May 17, 2020
5
0
10
0
That's the part number for the caddy the PSU goes into.

Acer Aspire, right?

Keep in mind that you're seeing the power it draws from the wall, which is AC. The PSU's rating is DC. DC output is going to be roughly 80%-85% of the AC.
Oh I see thank you. Yes it's an Acer Aspire Z5763. By what I can understand from what u said, only about 80% of the wattage from the AC reading is going into the PSU, so if the power draw is 220W AC, it's actually going to be around 200W going into the PSU right? So the upgrade won't max out my PSU im assuming
 
Oh I see thank you. Yes it's an Acer Aspire Z5763. By what I can understand from what u said, only about 80% of the wattage from the AC reading is going into the PSU, so if the power draw is 220W AC, it's actually going to be around 200W going into the PSU right? So the upgrade won't max out my PSU im assuming
Well there's a couple caveats here:

  1. TDP of a processor is the waste heat. The processor itself may consume more power. Not all of it goes to heat
  2. Power supplies age. As such they can lose as much as 20% of their capacity over time. Sometimes more.
  3. Running your supply close to it's limit 24/7 isn't good for longevity as it generates excess heat to run it near it's limit. The general rule of thumb is don't run it more than 80% capacity long term.
  4. Just because a supply is listed at 200 Watts doesn't mean it's 200 Watts on the main 12V rail, which is the most important.
I'm super conservative about my choices and choose power supplies that are 40% over my required power. I have supplies last 8+ years that way. I have a great 8 year old AX850 Corsair Gold which just keeps rocking on and the rails still look pretty clean. System never once had a power issue.
 

jonnyguru

Distinguished
Oh I see thank you. Yes it's an Acer Aspire Z5763. By what I can understand from what u said, only about 80% of the wattage from the AC reading is going into the PSU, so if the power draw is 220W AC, it's actually going to be around 200W going into the PSU right? So the upgrade won't max out my PSU im assuming
All of it is going into the PSU. Only 80 to 90% of it is coming back out.
 
May 17, 2020
5
0
10
0
All of it is going into the PSU. Only 80 to 90% of it is coming back out.
Oh ok. But the rating on the PSU is for the input power right? or is it for the 80 - 90% that's being generated as DC? Not sure if I should upgrade anymore but I'm still interested in this stuff
 
Last edited:
May 17, 2020
5
0
10
0
Well there's a couple caveats here:

  1. TDP of a processor is the waste heat. The processor itself may consume more power. Not all of it goes to heat
  2. Power supplies age. As such they can lose as much as 20% of their capacity over time. Sometimes more.
  3. Running your supply close to it's limit 24/7 isn't good for longevity as it generates excess heat to run it near it's limit. The general rule of thumb is don't run it more than 80% capacity long term.
  4. Just because a supply is listed at 200 Watts doesn't mean it's 200 Watts on the main 12V rail, which is the most important.
I'm super conservative about my choices and choose power supplies that are 40% over my required power. I have supplies last 8+ years that way. I have a great 8 year old AX850 Corsair Gold which just keeps rocking on and the rails still look pretty clean. System never once had a power issue.
I see, thanks for the advice. My PC is a bit old so the power supply probaby has aged. But the supply will only use around 80% of what my AC wattage meter says from what I've learnt about efficiency, so I calculate it will only have a max load of 78% and will normally run around 55-75% while gaming. Is it still risky in your opinion I'm not too sure myself?
 
Last edited:
I see, thanks for the advice. My PC is a bit old so the power supply probaby has aged. But the supply will only use around 80% of what my AC wattage meter says from what I've learnt about efficiency, so I calculate it will only have a max load of 78% and will normally run around 55-75% while gaming. Is it still risky in your opinion I'm not too sure myself?
I would say you are really pushing your limits. You could try it. But unexplained performance drops, system crashes, or shutdowns are a sign you pushed the PSU beyond it's limits.

To answer your question, the PSU wattage rating is the DC output side (As JonnyGuru stated) But not everybody list the output the same way. The good brands use the 12V output wattage as the power rating. While the cheap brands may add in the 3.3V, 5V, and 12V together to get a wattage output. So a cheap power supply may have like 10 Watts on the 3.3V, 25 Watts on the 5V, and 165W on the 12V and call that 200 Watts (10 + 25 + 165) Some cheap brands even list wattage with "peak" or "max" in the wattage phrasing indicating that they aren't meant to hold that power for more than a few ms.

A good power supply review will always do a torture test, where they run it at full power load for 5->10 minutes, and run it at 80% power load for a good 8->24hours.

I'm not sure but does this look like your power supply?

https://www.atxpowersupplies.com/powersupplies/Acer-Aspire-Z5761-power-supply-replacement.php
 
Reactions: Bazookatron263
May 17, 2020
5
0
10
0
I would say you are really pushing your limits. You could try it. But unexplained performance drops, system crashes, or shutdowns are a sign you pushed the PSU beyond it's limits.

To answer your question, the PSU wattage rating is the DC output side (As JonnyGuru stated) But not everybody list the output the same way. The good brands use the 12V output wattage as the power rating. While the cheap brands may add in the 3.3V, 5V, and 12V together to get a wattage output. So a cheap power supply may have like 10 Watts on the 3.3V, 25 Watts on the 5V, and 165W on the 12V and call that 200 Watts (10 + 25 + 165) Some cheap brands even list wattage with "peak" or "max" in the wattage phrasing indicating that they aren't meant to hold that power for more than a few ms.

A good power supply review will always do a torture test, where they run it at full power load for 5->10 minutes, and run it at 80% power load for a good 8->24hours.

I'm not sure but does this look like your power supply?

https://www.atxpowersupplies.com/powersupplies/Acer-Aspire-Z5761-power-supply-replacement.php
I see what you mean. And yes that's looks exactly like the one I have, been trying to search for it for ages but couldn't find the specs other thant the power rating thank you
 

ASK THE COMMUNITY

TRENDING THREADS