I want to go modular and have several questions.

Serradifalco

Senior member
May 27, 2007
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I am looking at the Seasonic X750 psu. It has 62A on the 12v rail.

List of hardware:

Gigabyte X58 mb
i7 920 oc'd to 3.7GHz
Noctua cpu cooler
GTX470 sli oc'd (very near future upgrade)
6 gigs ddr3 ram
2 internal 640gb WD hard drives
1 external dual hard drive
2 optical drives
1 floppy drive
5 case fans (3 are oversized > 200mm)
keyboard
wireless mouse

Questions:

1. I am upgrading to GTX470 sli which will be oc'd. Will the 750w Seasonic have enough power? I have researched this for a couple of days and gotten conflicting information. Hardocp says that it is recommended if you are not oc'ing the gpu's. But then again, there are individuals online running this type of setup with a 750w psu. I am lost on this one.
2. Will the new Sandybridge socket require a different cpu connector? I don't want to spend the money on a new psu and then dead end myself within a year.
3. What are the features to look at on a power supply when future-proofing is a consideration?

Thanks.
 

Meghan54

Lifer
Oct 18, 2009
11,684
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Well, if you don't mind running your 750W power supply right at its upper limits, sure, go ahead.

Personally, I really don't enjoy pushing any power supply to 90% of capacity or more.

If you're going to be OC'ing a 920 to anywhere around 4GHz, that by itself can consume north of 225W of power.

Anand's test of a stock running 470 with a very mildly OC'd 920 (3.33GHz) pulled 336W while playing Crysis, 60W less than a 480.

Now, extrapolate to SLI. Although Anand didn't test a 470 in SLI, we do have a 480 SLI tested and both a 470 and 480 as single cards.

Under Crysis, the 480 took, as I said, 60W more than a 470. Playing Crysis with a 480 SLI setup, the entire system drew 668W, so a 470 SLI should be around 550W. But the OC on the 920 was very low and so was its power draw. Get up to 4GHz and you'll add in quite a bit more power draw for the cpu than Anand's testing showed.

So, with a 470 SLI setup, at stock clocks, and a fairly heavy OC'd 920 at 4GHz, a reasonable OC, you'll be passing 600W while playing a typical game like Crysis or while stress testing like with Furmark. OC the cards and 600W will be nothing but a dream while playing a demanding game or stress testing.

Sure, the 750W ps will handle it....but you're going to be within 100W of total output, and with anything electrical, the closer you run it to its rated output capacity, the shorter its life will be and the hotter it'll run.

That 750W should be the minimum you should look at. I'd almost suggest something like a Corsair 850HX instead....give a bit more headroom....just in case.
 

vanilla guerilla

Senior member
Oct 26, 2009
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he's right, you know. and he didnt even account for efficiency or temp of the 750w psu, both of which will decrease continuous power. and if you think that you will be running a more powerful or next gen sli rig in the next year or 2, maybe you should think about 1000 watts.
 
Last edited:

Stefan Payne

Senior member
Dec 24, 2009
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The better modern PSUs are rated at 50°C, so that's not a big problem.
It's rater uncommon to rate a PSU at 25°C, such as the Coolermaster GX Series...

And don't forget that in most modern cases the PSU is found at the bottom where it sucks in cold air from outside the case (and vacuums the carpet a little)...

PS: why would anyone want a GTX470 SLI?!
 

TemjinGold

Diamond Member
Dec 16, 2006
3,050
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Efficiency and temp shouldn't factor in for a quality PSU. But Meghan is right in that you should really look at an 850 watt minimum if you plan on SLIing 470s.
 

Serradifalco

Senior member
May 27, 2007
363
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Well, if you don't mind running your 750W power supply right at its upper limits, sure, go ahead.

Personally, I really don't enjoy pushing any power supply to 90% of capacity or more.

If you're going to be OC'ing a 920 to anywhere around 4GHz, that by itself can consume north of 225W of power.

Anand's test of a stock running 470 with a very mildly OC'd 920 (3.33GHz) pulled 336W while playing Crysis, 60W less than a 480.

Now, extrapolate to SLI. Although Anand didn't test a 470 in SLI, we do have a 480 SLI tested and both a 470 and 480 as single cards.

Under Crysis, the 480 took, as I said, 60W more than a 470. Playing Crysis with a 480 SLI setup, the entire system drew 668W, so a 470 SLI should be around 550W. But the OC on the 920 was very low and so was its power draw. Get up to 4GHz and you'll add in quite a bit more power draw for the cpu than Anand's testing showed.

So, with a 470 SLI setup, at stock clocks, and a fairly heavy OC'd 920 at 4GHz, a reasonable OC, you'll be passing 600W while playing a typical game like Crysis or while stress testing like with Furmark. OC the cards and 600W will be nothing but a dream while playing a demanding game or stress testing.

Sure, the 750W ps will handle it....but you're going to be within 100W of total output, and with anything electrical, the closer you run it to its rated output capacity, the shorter its life will be and the hotter it'll run.

That 750W should be the minimum you should look at. I'd almost suggest something like a Corsair 850HX instead....give a bit more headroom....just in case.

You make some really good points! Is there anything fully modular like the Seasonic in that wattage range?

The better modern PSUs are rated at 50°C, so that's not a big problem.
It's rater uncommon to rate a PSU at 25°C, such as the Coolermaster GX Series...

And don't forget that in most modern cases the PSU is found at the bottom where it sucks in cold air from outside the case (and vacuums the carpet a little)...

PS: why would anyone want a GTX470 SLI?!

I think a single GTX470 is not much of a gain from GTX260 sli, if at all. Of course you pick up DX11, but that alone currently is not worth it.
 

Meghan54

Lifer
Oct 18, 2009
11,684
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For fully modular, HOOfan has listed about the only one that is high enough quality to be considered.

Consider your need for a fully modular power supply. Why do you need a fully modular power supply?

You are going to need, at a minimum, a 24-pin motherboard connector, 2 PCI-e connectors and a 4+4/8-pin ATX/EPS connector....so I'd also consider power supplies with those cables hard wired, which is why I mentioned the Corsair 850HX as a suggestion. There are other units equally as capable and set up essentially the same....hard wired cabling for the essential cables, all others modular.
 

Serradifalco

Senior member
May 27, 2007
363
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For fully modular, HOOfan has listed about the only one that is high enough quality to be considered.

Consider your need for a fully modular power supply. Why do you need a fully modular power supply?

You are going to need, at a minimum, a 24-pin motherboard connector, 2 PCI-e connectors and a 4+4/8-pin ATX/EPS connector....so I'd also consider power supplies with those cables hard wired, which is why I mentioned the Corsair 850HX as a suggestion. There are other units equally as capable and set up essentially the same....hard wired cabling for the essential cables, all others modular.

The 850HX is not currently available anywhere. It is sold out! I have searched all of the major etailers. I am ok with the main cables being hard wired. Any other considerations? I need a modular power supply with fairly long cables. My HAF 932 case is very large and I like to route the cables behind the mb.
 

Big Lar

Diamond Member
Oct 16, 1999
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Check out the Corsair TX950, it's not modular but fits what you need very well.

Larry
 

Meghan54

Lifer
Oct 18, 2009
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killster1

Banned
Mar 15, 2007
6,205
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i use the affordable corsair 750hx's they have 7 year warranty. but the silverstone modular one looks REALLY nice minus no power switch (at least the 750 didnt have one)