How much PSU do I really need?

[DigitalCancer]

Hey Guys,

I wanted to run this past you guys to determine if I'm thinking correctly or not.

I'm looking at building a little mini-gaming machine and I'm not sure if a 450w psu will suffice or should I go with a 600w?

Internals will be:

i5 4670/4690
500 SSD
GTX 970 FTW
2-3 case fans
no optical

I won't be O/C'ing anything...just running stock...I'm leaning toward the 600w but wanted to hear some recommendations


Thanks in advance!

 

[Deders]

This should be in the PSU section but I would say 500w will be fine just to give you good headroom so the PSU can run optimally.

Even though the 970's power draw average is fairly low it can spike for the odd millisecond here and there as the power management kicks in.

 

[DigitalCancer]

I didn't even notice there was a psu section! Anyway, I think I have the confirmation I need anyway after doing a little more research. I'm building an ITX machine, so an SFX psu is what I have to get, 600w being the step up from a 450w...so...should future proof me as well as keep me stable. ^_^

 

[ctsoth]

The system in my signature is powered by an Antec 400w power supply, I forget the specific model but it is an 80+ bronze model. It's either an earthwatts or a neo eco.

I've been running this power supply since early 2012 and I have never had any issues. My previous system never peaked over 200w from the wall, and being that I am not sure where my kilowatt sensor is, I am not sure what I pull from the wall on my new system, but being that my new processor is more energy efficient than my old one I have no concerns.

Were I in your position I would likely get a 500 or 600w high quality PSU, and just make whatever you buy has the proper connections for your GPU. Honestly there is no way the specs you listed with single GPU are going to overload a 500w power supply, or even come close to doing so.

 

[EliteRetard]

Almost exact system I just ordered. 4790k, GTX970, 16GB, 500GB SSD

Peak may be just over 300w, so a good 450w is plenty (like the one in the SG05)
An AMD 290 card may push the system just over 400w, which I didn't want to risk.
I also didn't want the extra heat added to the tiny case, so I chose performance/watt over performance/dollar.

You can use TDP as a good estimate, those Intel CPUs are 90w and the 970 is rated 150w (max ~225w w/ 2x 6 pin). Add 5w each for RAM MOBO SSD and fans...that's ~20w. If you hit peak load on all parts that's about 335w. Add ~25% for moderate OC and you got 420w peak. Fine for a 450w continuous unit.

Now typically high end GPU's do use more power, so if you want to plan for that upgrade then yeah the next step up to 600w would allow you to fit in current or next gen 300w cards with plenty of room and even a big OC across the board (as long as you can handle the heat). There are even some X99 ITX MOBO's and 600w should allow a 6-8 core system as well.

Reality is most people don't need a lot of power...those 1kw+ PSUs are really only for multi-GPU systems.

 

[Xpage]

I'd go with a 450-500W, maybe 550W if you plan on adding a ton more stuff in later but anything higher than 500W is overkill.