Question Powering up GPU with a separate PSU, does it matter if i use a psu with lower wattage than the recommended for the GPU?

[olcatt]

i bought an RX 570 that needs a 500w PSU but the PSU i ordered for it is cancelled due to being out of stock(how irresponsible of the seller, i even waited for 5 days just to receive an email of cancellation by the seller)
this has really wasted my time now so i want to buy a psu in my local store, but the only available ones are 400w

QUESTION:
does it matter if i power my gpu(which needs 500w) with a 400w power supply?

i'm btw gonna run a dual psu system. the new psu going to the gpu only. don't worry i'll short the psu with a psu tester


my pc right now is this:
fricking optiplex 7010 sff(gonna use a riser extender)
fricking proprietary mobo
8gb ram ddr3
i5 3470

ik the look of this thing would be horrible but that's what's given to me so i'm just gonna do my all to upgrade it

 

[Metal Messiah.]

Those power system requirements are for the FULL system/OC under load, not just the GPU alone. While a 400 Watts PSU might also work, but there is a reason why Nvidia/AMD recommend a minimum Wattage PSU, for safety reasons.

What's the Make and MODEL number of your 400 Watts PSU though ?

 

[Metal Messiah.]

BTW, I just wanted to mention this as well. You might be already knowing all this though.

Wattage number is not always important. The quality and the make matters. The main concern is the "quality" of the power, the quality of the components used/CAPS, as well as the total AMP drawn on the +12V RAIL (output), the efficiency under load, "ripple suppression", among other factors.

The total wattage number of any PSU is not always really the most important deciding factor, primary concern is the 'quality' of power it produces, and the total capacity of the 12V source etc.

Also make a note------------> If suppose you have a 500W PSU installed on any RIG, then that does not mean that it will always draw the full wattage/500 W. Nope....... The amount of power drawn is determined by the number of components on that rig/computer, and how much they actually require. The amount of power drawn will only be equal to what is required, and not more.

Suppose, if all the components of a rig require 400 W to run, then the "load" on the PSU will be 400 W, and hence the power draw of that particular PC will always be 400 W (depending on the efficiency obviously), regardless of whether a 500 Watt or a 1000 W PSU is installed. PSU efficiency is a different matter though, as how well the PSU converts the AC power it receives from the outlet, to DC.

Any electricity which is not converted from AC to DC, is given off as heat. A PLATINUM certified PSU might help you save a little on your electricity bill, over a year, though this depends on many other factors as well. Because any high quality Tier 1 platinum certified PSU is rated for at least 90% efficiency at 20% load, 92% at 50% load, and 89% at 100% load (just a rough estimate).

 

[olcatt]

BTW, I just wanted to mention this as well. You might be already knowing all this though.

Wattage number is not always important. The quality and the make matters. The main concern is the "quality" of the power, the quality of the components used/CAPS, as well as the total AMP drawn on the +12V RAIL (output), the efficiency under load, "ripple suppression", among other factors.

The total wattage number of any PSU is not always really the most important deciding factor, primary concern is the 'quality' of power it produces, and the total capacity of the 12V source etc.

Also make a note------------> If suppose you have a 500W PSU installed on any RIG, then that does not mean that it will always draw the full wattage/500 W. Nope....... The amount of power drawn is determined by the number of components on that rig/computer, and how much they actually require. The amount of power drawn will only be equal to what is required, and not more.

Suppose, if all the components of a rig require 400 W to run, then the "load" on the PSU will be 400 W, and hence the power draw of that particular PC will always be 400 W (depending on the efficiency obviously), regardless of whether a 500 Watt or a 1000 W PSU is installed. PSU efficiency is a different matter though, as how well the PSU converts the AC power it receives from the outlet, to DC.

Any electricity which is not converted from AC to DC, is given off as heat. A PLATINUM certified PSU might help you save a little on your electricity bill, over a year, though this depends on many other factors as well. Because any high quality Tier 1 platinum certified PSU is rated for at least 90% efficiency at 20% load, 92% at 50% load, and 89% at 100% load (just a rough estimate).

thanks for the reply.
i did not ask what model it was because they said they only have 400w so i fat out rejected them
anyways, i'm also asking this for future references if this method could work then i may do this again
regarding the psu power drawn, i watched some video on linus tech tips covering that so there's really no problem

 

[hang-the-9]

Best way to get your system to run a gaming video card for lowest price would be to remove the CPU, RAM and hard drive. Buy a motherboard, case and power supply for those, install Windows clean due to motherboard swap. You can probably find used parts since you look to be trying to save money on this, a lot of people upgrade and sell their old setups.

 

[olcatt]

Best way to get your system to run a gaming video card for lowest price would be to remove the CPU, RAM and hard drive. Buy a motherboard, case and power supply for those, install Windows clean due to motherboard swap. You can probably find used parts since you look to be trying to save money on this, a lot of people upgrade and sell their old setups.

that's what i'm aiming for originally, but the only monitor i had was vga so i ended up buying a new monitor that supports digital signal because i hate active adapters, just the response time it adds is so irritating because i play a lot of rhythm games.
i'm an fps and latency first guy.

 

[Metal Messiah.]

What's the make/model of your MONITOR ?

 

[olcatt]

What's the make/model of your MONITOR ?

it's a dell p2414h
has 1x VGA 1x DVI-D and 1x Display Port
i got it for 90 USD if you convert it from 4,700 PHP
i wanted the 2012 version due to lower response time but this is what's available on the market for 2nd hand
the rx 570 i got also has DVI-D only