Looking for a good power supply

[Cav3Johnson]

Im planning on getting a new power supply (my rx-480 cant use my current one) and i need help deciding on one to get. Ive gone to sites like pc part picker and figured out i need a at a bare minimum 550w, but will probably aim for something between 650 and 750. I do have one psu that caught my intrest, as it is a corsair unit.  

http://www.bestbuy.com/site/corsair-cx-series-modular-cx750m-750w-atx-power-supply-black/8324202.p?skuId=8324202&ref=212&loc=1&ksid=7c4c5e32-be9f-48d7-984a-7ac72b6d3e73&ksprof_id=8&ksaffcode=pg199269&ksdevice=m&lsft=ref:212,loc:2

 

is this a good choice? Im very new to the whole "upgrading pc" department, and have already messed up once by not checking my psu before i got my new gpu, so i want to be doubly sure something like this would work. 

[Guest]

Please tell us your budget and your specs

[Cav3Johnson]

1 minute ago, deXxterlab97 said:

Please tell us your budget and your specs

 Budget is between $50 and $90

specs are currently:

CPU: AMD FX-4100

MoBoard: AMD 760G

GPU (not in use yet) RX-480

8GB RAM

currently have a 300w psu

[Guest]

3 minutes ago, Cav3Johnson said:

 Budget is between $50 and $90

specs are currently:

CPU: AMD FX-4100

MoBoard: AMD 760G

GPU (not in use yet) RX-480

8GB RAM

currently have a 300w psu

 

And this PSU is really really good

http://www.outletpc.com/oa2432-evga-220-g2-0650-y1.html?utm_source=oa2432-evga-220-g2-0650-y1&utm_medium=shopping%2Bengine&utm_campaign=pcpartpicker&utm_content=EVGA%2B-%2BPower Supplies > ATX Power Supply

 

[iRileyx]

I'd try and get a grey label CX if you can, you won't need close to 500 either, a 450 would be plenty.

[Cav3Johnson]

2 minutes ago, deXxterlab97 said:

 

And this PSU is really really good

http://www.outletpc.com/oa2432-evga-220-g2-0650-y1.html?utm_source=oa2432-evga-220-g2-0650-y1&utm_medium=shopping%2Bengine&utm_campaign=pcpartpicker&utm_content=EVGA%2B-%2BPower Supplies > ATX Power Supply

 

That psu seems very expensive for being weaker then the psu i mentioned. Why is a 650w nearly $20 more then a 750w?

[iRileyx]

1 minute ago, Cav3Johnson said:

That psu seems very expensive for being weaker then the psu i mentioned. Why is a 650w nearly $20 more then a 750w?

The G2 is a tier 1 power supply, the green label CXm's are only tier 4.
Its the quality that makes the price difference, not the wattage.

[Cav3Johnson]

2 minutes ago, RKRiley said:

I'd try and get a grey label CX if you can, you won't need close to 500 either, a 450 would be plenty.

The minimum psu requirement for a rx-480 is 500w though...

[iRileyx]

1 minute ago, Cav3Johnson said:

The minimum psu requirement for a rx-480 is 500w though...

Hah yeah, they say that, it really isnt, look at its actual power usage.. mine overclocked to 1420mhz never uses over 120 watts according to msi afterburner.

[Guest]

1 minute ago, Cav3Johnson said:

The minimum psu requirement for a rx-480 is 500w though...

That's what they always say to exaggerating things

[Cav3Johnson]

2 minutes ago, RKRiley said:

The G2 is a tier 1 power supply, the green label CXm's are only tier 4.
Its the quality that makes the price difference, not the wattage.

Would it be possible to find one under $90 then? I just put ~180 towards a new gpu and this extra money for a psu was not expected in the budget. 

[Cav3Johnson]

2 minutes ago, deXxterlab97 said:

That's what they always say to exaggerating things

Ok, so i would be fine with a 500 or 600w psu?

[Guest]

2 minutes ago, Cav3Johnson said:

Would it be possible to find one under $90 then? I just put ~180 towards a new gpu and this extra money for a psu was not expected in the budget. 

EVGA G2550w

[Cav3Johnson]

3 minutes ago, RKRiley said:

Hah yeah, they say that, it really isnt, look at its actual power usage.. mine overclocked to 1420mhz never uses over 120 watts according to msi afterburner.

Thats comforting in a way 

[Spuriae]

I agree with the rest of you that he only needs a 450W PSU, but there's a reason minimum power supply sizes exist. 

 

The R9 390X, for instance, was rated at 275W. If you checked afterburner, you'd probably see things in the low 300 range. Guru3D even calculated the card at 258W.

 

 

The problem is transients. Your card can't detect short power spikes; only an oscilloscope can (if your card could, everyone would be selling their oscilloscopes and buying GPU's for power testing). This is what the power draw on the 390X really looks like:

 

 

Sure, the card only draws less than 300W on average. Thanks to power spikes that the user can't see, however, you'd need a PSU capable of delivering 500W just to keep the card functioning without an overclock! On top of that, power spikes are transient loads, which is something most small PSU's tend to be poor at handling. If you're running the system with a high power (or an AMD) CPU, the minimum power supply of 700W suddenly seems reasonable, at least from AMD's point of view. Of course, not everyone will be running such a high-power system and can afford to cut back on the wattage; the minimum power supply is mostly there to account for the worst-case scenario.

 

The 480 still will only spike to ~300W, so OP is fine getting a 450W PSU. That "minimum power supply" spec is there for a reason, though.

[Cav3Johnson]

40 minutes ago, Nimrodor said:

I agree with the rest of you that he only needs a 450W PSU, but there's a reason minimum power supply sizes exist. 

 

The R9 390X, for instance, was rated at 275W. If you checked afterburner, you'd probably see things in the low 300 range. Guru3D even calculated the card at 258W.

 

 

The problem is transients. Your card can't detect short power spikes; only an oscilloscope can (if your card could, everyone would be selling their oscilloscopes and buying GPU's for power testing). This is what the power draw on the 390X really looks like:

 

 

Sure, the card only draws less than 300W on average. Thanks to power spikes that the user can't see, however, you'd need a PSU capable of delivering 500W just to keep the card functioning without an overclock! On top of that, power spikes are transient loads, which is something most small PSU's tend to be poor at handling. If you're running the system with a high power (or an AMD) CPU, the minimum power supply of 700W suddenly seems reasonable, at least from AMD's point of view. Of course, not everyone will be running such a high-power system and can afford to cut back on the wattage; the minimum power supply is mostly there to account for the worst-case scenario.

 

The 480 still will only spike to ~300W, so OP is fine getting a 450W PSU. That "minimum power supply" spec is there for a reason, though.

Thank you for this info. 

[STRMfrmXMN]

1 hour ago, Cav3Johnson said:

Would it be possible to find one under $90 then? I just put ~180 towards a new gpu and this extra money for a psu was not expected in the budget. 

There are plenty of good PSUs under $90 that I can easily recommend for a 480. Get an EVGA GQ/GS/G2/B2, Seasonic G-series/S12/M12, Corsair CX450M, Antec HCG, Corsair RMx - the list could go on.

[Ununhexium116]

Although the card may not need a psu capable of 750w, most psu's are most efficient at ~50-60%. I run a cx750m and an rx 480 as well. Although i've only ever measured 350w from the wall, the cx750m should last for a long time and be able to run almost anything you upgrade to.