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PSU upgrade questions

S

s1175290

Limp Gawd
Joined
Nov 3, 2010
Messages
133
I'm making some changes to my rig and I'm thinking I'm going to need to upgrade the PSU. I entered everything in to a calculator and came up with a minimum of 775w, and a recommendation of 825w.

System will consist of the following:

2600k (O/C to 4.4ghz)
16gb RAM (4 x 4gb)
3 x 7200 RPM
5 x SSD
PCIe RAID card
5870 x 2 cards (not overclocked)
DVDRW drive
Bluray drive
8 case fans

Will an 850w power supply be enough? Newegg has this Corsair on sale for $139AR

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139011

It's worth mentioning that I'm looking for a couple of things in a new power supply:

1. Must be modular (not fully, but at least semi-modular)
2. Looking for a top tier power supply (Corsair, Seasonic, etc.)

Would I benefit by stepping up to something with a little more power, or will the Corsair one above be enough?
 
To begin with, stop using online calculators, they're trash.. that system only needs a solid 650W unit, 700W maybe(just to allow for some major overclocks on the cards).. what PSU do you have currently?
 
Profumo said:
To begin with, stop using online calculators, they're trash.. that system only needs a solid 650W unit, 700W maybe(just to allow for some major overclocks on the cards).. what PSU do you have currently?
Click to expand...

I figured I had to start somewhere. This calculator seemed to be regarded somewhat decently:

http://extreme.outervision.com/psucalculatorlite.jsp

To answer your question, I have a 750w Antec unit. I'm in the process of adding a few hard drives, the second 5870, and a blu-ray drive. I wasn't quite certain the current unit would cut it, and I could actually use a spare PSU. I was going to take the Antec out of service and use it as the spare/test unit and upgrade to the Corsair.

If the Antec is enough, I can pick up a much cheaper spare/test unit. Any other feedback?
 
Nothing wrong with calculators. They give you a good idea of what you need. Also, there is a big difference between a Diablotech 750 watt power supply and Seasonic 750 watt supply so that's part of why they'll give you a little headroom in their recommendations. You wont always get the wattage the label claims on lesser quality power supplies which, sadly, seem to take up the majority of the PSU market.

But yeah, your current Antec 750 is a quality unit and will be enough.
 
Last edited:
Profumo said:
To begin with, stop using online calculators, they're trash.. that system only needs a solid 650W unit, 700W maybe(just to allow for some major overclocks on the cards).. what PSU do you have currently?
Click to expand...

It's smart to use online calculators, and NOT smart for the OP to take your advice. Why do you want him to buy a PSU that will literally be the same rating as what he will be pulling from the wall at max load? You really enjoy living on the edge like that? His efficiency will be down, the voltages may sag ever so slightly, and the noise levels will be high. You always want a cushion. Don't listen to the guy. Grab a decent 850W and you're good to do. No need to penny pinch here....
 
s1175290 said:
I figured I had to start somewhere. This calculator seemed to be regarded somewhat decently:

http://extreme.outervision.com/psucalculatorlite.jsp

To answer your question, I have a 750w Antec unit. I'm in the process of adding a few hard drives, the second 5870, and a blu-ray drive. I wasn't quite certain the current unit would cut it, and I could actually use a spare PSU. I was going to take the Antec out of service and use it as the spare/test unit and upgrade to the Corsair.

If the Antec is enough, I can pick up a much cheaper spare/test unit. Any other feedback?
Click to expand...

What specific Antec 750W unit do you have?

On calculators, the outervision one is trash as pretty much all of them except for the one made by Phaedrus at overclock.net which is pretty usable and precise but don't expect 100% accuracy from that one either..

5870s are 200W cards, the 2600K @ 4.4Ghz(below 1.4v) is a 120W CPU at most... everything else you listed sums up to about 50W.
Adding all the above you end up with a <600W system at full load(not a commonly occurring situation unless you're running some distributed computing app).. 850W would be pointless overkill and wasted money.
 
Falkentyne said:
It's smart to use online calculators, and NOT smart for the OP to take your advice. Why do you want him to buy a PSU that will literally be the same rating as what he will be pulling from the wall at max load? You really enjoy living on the edge like that? His efficiency will be down, the voltages may sag ever so slightly, and the noise levels will be high. You always want a cushion. Don't listen to the guy. Grab a decent 850W and you're good to do. No need to penny pinch here....
Click to expand...

Uh, no. Using your argument, pulling 650 watts from the wall would be pulling 520-585 watts from the power supply, depending on the efficiency level of the power supply (I gave 80% to 90%, which is typical of the majority of power supplies). Even with the 585 watt pull, that's 65 watts of headroom you have with a 650 watt power supply. That's plenty of cushion.

Voltages do not sag significantly enough to matter in quality power supplies. Targeting 50% load for max efficiency is just a myth, and a stupid thing to do. Noise levels will not be high, the fans on the graphics cards will be noisier.
 
Falkentyne said:
It's smart to use online calculators, and NOT smart for the OP to take your advice. Why do you want him to buy a PSU that will literally be the same rating as what he will be pulling from the wall at max load? You really enjoy living on the edge like that? His efficiency will be down, the voltages may sag ever so slightly, and the noise levels will be high. You always want a cushion. Don't listen to the guy. Grab a decent 850W and you're good to do. No need to penny pinch here....
Click to expand...

Seriously? Just no.

I'm all for recommending a bit more than you need (Never know when you "accidentally" end up with some new hardware ;) ) but this is ridiculous. He'd be fine with that, I doubt he's drawing more than 560W DC so I doubt it'll be a problem.
EDIT: Plus online calculators are hilariously inaccurate. I dunno what you're on about there.

As for the OP, if you want to have a spare unit that's definitely a good one to have as a spare, and I'd wager you'd be fine with 850W unless you plan on putting in significantly more power hungry hardware in the near future.
 
Uberbob102000 said:
Seriously? Just no.

I'm all for recommending a bit more than you need (Never know when you "accidentally" end up with some new hardware ;) ) but this is ridiculous. He'd be fine with that, I doubt he's drawing more than 560W DC so I doubt it'll be a problem.
EDIT: Plus online calculators are hilariously inaccurate. I dunno what you're on about there.

As for the OP, if you want to have a spare unit that's definitely a good one to have as a spare, and I'd wager you'd be fine with 850W unless you plan on putting in significantly more power hungry hardware in the near future.
Click to expand...

In fact, those online calculators take into account the multitude of shitty PSUs that can't handle even half of their labeled wattage claims.
 
Man, so much hate here....
I think I'll go hide in my man cave where I'm safe.
Next thing some shortbus rider is going to tell me is that windows calculator is worthless, too. I guess some people here are just so OLD now that they forgot all about the value of BASIC MATH.

PSU calculators are a USEFUL tool. And tools are just that, tools. Smart people (like me) use them as a valuable aid which makes our lives a bit easier. Don't call something worthless because you chose to shove a screwdriver up a woman's behind when you should have used your package instead. Screwdrivers are for screws. Even though the shape might tell you otherwise.

You know EXACTLY what I'm talking about, even though my analogy is a bit twisted.

Glad you decided on a quality 750w PSU.
 
Falkentyne said:
Man, so much hate here....
I think I'll go hide in my man cave where I'm safe.
Next thing some shortbus rider is going to tell me is that windows calculator is worthless, too. I guess some people here are just so OLD now that they forgot all about the value of BASIC MATH.

PSU calculators are a USEFUL tool. And tools are just that, tools. Smart people (like me) use them as a valuable aid which makes our lives a bit easier. Don't call something worthless because you chose to shove a screwdriver up a woman's behind when you should have used your package instead. Screwdrivers are for screws. Even though the shape might tell you otherwise.

You know EXACTLY what I'm talking about, even though my analogy is a bit twisted.
Click to expand...
Please stop. You aren't helping.
 
s1175290 said:
Newegg has this Corsair on sale for $139AR

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139011
Click to expand...


I ended up finding a better code for 15% off. I also had a free $20 GC to Newegg from Google (from the Google Offers fiasco a couple of weeks ago). This brought the price down to $105 with free 2 day shipping. I thought that price was too good to pass up, especially since I was in the market for a spare PSU anyway. I will probably install this in the rig and move the Antec to the back up. But it's nice to have choices :)
 
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