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400W PSU enough?

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July 31, 2006 2:15:13 AM

I'm looking at building a new system with the following components:
Intel Core 2 Duo E6600 2.4GHz
GeForce 7800 GTX 512MB PCI Express
Seagate 200GB 7200rpm HDD
1x dvd-rw drive
1x audigy 2 ZS


Will this system run ok on a 400W PSU, or will I need to get a larger one? If so, how many Watts? If 400W is ok, is it cutting it pretty fine?

Bit of a noob with this, btw.
Cheers

More about : 400w psu

July 31, 2006 3:16:27 AM

Seriously doubt 400w will be enough for the GTX. I ran my system with a 400w for a while.. but it blew up. Had to get a new mobo.

amd 64 3200
dfi slidr
2gb gskil
7800gt
July 31, 2006 3:16:32 AM

Quote:
I'm looking at building a new system with the following components:
Intel Core 2 Duo E6600 2.4GHz
GeForce 7800 GTX 512MB PCI Express
Seagate 200GB 7200rpm HDD
1x dvd-rw drive
1x audigy 2 ZS


Will this system run ok on a 400W PSU, or will I need to get a larger one? If so, how many Watts? If 400W is ok, is it cutting it pretty fine?

Bit of a noob with this, btw.
Cheers


you might have issues if you add 3+ hard disks and SLI graphics. looking at your stats I'd say you have a lot of room to move around.
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July 31, 2006 3:18:58 AM

I had a bad experience with mine, 400w is technically enough goin on the specs from nvidia >.<.
July 31, 2006 3:42:55 AM

Well, the components you listed would roughly require around 250 - 260 watts to power at idle usage - this is, of course, with no overclocking or taking into consideration any usb devices or bling (LED, Cold Cathode) or the number of fans in use for cooling.

That being said, you would do well to have a PSU with multiple 12v rails. A safe amperage across them would be at least around a 17 amp average for each one.
July 31, 2006 3:51:09 AM

You'll need more power. Since you're building the system new, why not spend a few extra bucks and get a 550 wt? That will allow for some future expansion without having to go out and buy yet another power supply.
July 31, 2006 3:57:27 AM

I'd have to agree here, if you can afford it. You see, the power calculations I did not consider your cooling methods and you didn't list the RAM you use. I'm always for "future-proofing" and, if you intend on having a PSU that you would like to carry you into the future for a few years you might consider Sailers advice.

Case in point - the new Nvidia G80 GPUs are supposed to demand 175 watts and the R600 from ATI is even more at 200 watts - those are hefty demands and do not take into account any overclocking (and twice the power demands of a 7800 GTX 512).
July 31, 2006 4:36:53 AM

A slightly more powerful PSU won't cost you that much. Its a safer bet and you may end up spending less money since it won't "blow up"
July 31, 2006 5:47:52 AM

No one is really saying it won't work. We're just giving him a choice so that he can upgrade for the future.

The Nvidia 7800 GTX 512 requires a minimum 350 watt (500 watt for SLI) PSU with 22 amps from the 12v rails. Some companies like BFG, XFX, MSI and Giga-byte, require a minimum 400 watts with 26 amps.

These recommendations were for a more powerful PSU for future proofing and with adequate enough amps for his components as the cpu, HDDs, optical drives, fans will also be drawing off 12v rail as well.
July 31, 2006 6:09:16 AM

those requirements are always off. They over require so they dont have to deal with customers who didnt meet the exagerated requirements.
July 31, 2006 8:04:01 AM

As Pengwin said, if its a good 400w PSU then you will be able to get along fine.

A single GTX/FX-60 rig for example draws about 310w peak from the mains, for example.

It's a shame, I have a spare Antec NeoHE 430w which I'd sell you but I need it 'cos the PSU in my old PC died.

If you are overclocking much, though, then I suggest getting a PSU with more headroom - and at the same time picking something quiet (like the NeoHE series).

In terms of wattage, technically a 400w PSU will do fine, however as previously stated the main problem will be providing enough current on the 12v rail(s) for that beast of a graphics card.

Interestingly, balancing the load of the PSU with additional drives actually increases the amps available on the 12v rail - this is because of the way PSUs work. Sounds daft? Read this:

http://www.extremetech.com/article2/0,1697,1933038,00.a...

The article is based around SLI (so don't think you need a 650w Silverstone!) but you get the idea.

However, if you have a generic PSU and need a new one, you might as well take the plunge and go for something with headroom such as a 550w+. Rumour on the street is that future graphics card power consumption is gonna go UP, not DOWN!

If you ever upgrade to an SLI rig, then you will be able to run it with this (but I'd recommend adding another HDD to balance the load).
July 31, 2006 1:18:26 PM

Quote:
Interestingly, balancing the load of the PSU with additional drives actually increases the amps available on the 12v rail - this is because of the way PSUs work. Sounds daft? Read this:

http://www.extremetech.com/article2/0,1697,1933038,00.a...


A few months ago, I had just those problems but the prescribed workaround didn't work for an Enermax Liberty 620, an Xclio 800 or a Coolmax 850. On paper, all three had plenty of watts. I tried many variations of sequentially removing devices, putting them on different rails, etc. I called up their tech people, the engineers that spec'ed their units, etc., and got tons of advice that didn't work. Then I got in touch with a lady engineer at FSP and she talked about the load sharing design they use on their better four-12V rail units. Turns out that PCP&C and mushkin use similar designs that are made at the same plant as the FSP (and someone here posted that the 4-rail OCZs are made at the same place). Anyway, when the rails are imbalanced, the PS can adjust automatically (within the limit of something like a max of 26 or 28A on a single rail).

Back at that time, I couldn't find an FSP 700 watt unit anywhere and since I was dead in the water, I talked to OCZ on the phone and ended up talking to the guy that spec'ed their units. He was a real cool guy, very informative and very up-front. He personally guaranteed that their 700 watt Gamextreme would run my system. So I got it and he was right - it's solid as a rock. Not long after that, I talked to a couple of engineers at mushkin and when they told me they were using the same plant as PCP&C and FSP, my ears perked up. Then I got to look at the internals of the mushkin and the FSP and I could then see why mushkin charges more - theirs is an excellent unit for a dual-card overclocked PC. So I got one for the box I was building at the time (Opty 170, XFired 1900s) and it never even gets hot, even looping 3DM06 maxed out.

Quote:
Rumour on the street is that future graphics card power consumption is gonna go UP, not DOWN!


True. We're gonna see some meltdowns, guaranteed!

Quote:
If you ever upgrade to an SLI rig, then you will be able to run it with this (but I'd recommend adding another HDD to balance the load).


Or, just get a PCP&C, FSP, OCZ or mushkin, since they do the balancing act for you - you just build and run! (And open your wallet WIIDDDEEE)
August 1, 2006 12:33:54 AM

Cheers for the quick response.
I actually bought a Thermaltake Soprano case with 400W psu about 8months ago, and I'm only just getting around to upgrading. Should be relatively simple to buy a bigger psu and put it into the case?

yea I'm thinking I may as well get a bigger one now, without having to worry about it in the future. What is this about extra HDD to balance the load?

Cheers
August 1, 2006 12:36:15 AM

Oh and I probably won't be overclocking anytime soon, I'm a pretty casual gamer. Probably won't make the move to SLI until my next upgrade, cos I can't really justify the cost, and this should pretty much satisfy my meagre needs :D 
August 1, 2006 12:41:12 AM

Check the rails on the next PSU that you get. Don't get anything with less than a 17 amp average.

Antec, PCP&C, Silverstone, OCZ, Seasonic, Enermax or Mushkin

Check out this review of highend PSUs

http://www.bytesizedreviews.com/?rev_id=302

It will provide you with some insight
August 1, 2006 12:56:15 AM

I'd get at least a 500W PSU with dual 12V rails. Also, I'd get a 7900GTX rather than the 512MB 7800GTX. The 7900 is a little bit faster, but it's a LOT cheaper and readily available.
August 1, 2006 1:57:08 AM

Quote:
I'd get at least a 500W PSU with dual 12V rails. Also, I'd get a 7900GTX rather than the 512MB 7800GTX. The 7900 is a little bit faster, but it's a LOT cheaper and readily available.


he may already have a 7800GTX on hand
August 1, 2006 2:20:48 AM

The only 7900GTX in the retailers I buy from are more expensive than the 7800GTX. Apparently they have them in stock, too. The 256mb 7800GTX is also considerably cheaper than the 512mb. Is this a good option for me?

I'm looking at either:
Enermax Noisetaker series EG701AX-VE 600W @ $239 New Zealand dollars ($148USD)
or:
Silverstone ST60F 600W @ $250 NZD ($154USD)

PROVIDED I can fit it into my current case?
Or would 500-550W versions made by these manufacturers suffice, as they are quite substantially cheaper?
Cheers
August 1, 2006 2:24:27 AM

Quote:
The only 7900GTX in the retailers I buy from are more expensive than the 7800GTX. Apparently they have them in stock, too. The 256mb 7800GTX is also considerably cheaper than the 512mb. Is this a good option for me?

I'm looking at either:
Enermax Noisetaker series EG701AX-VE 600W @ $239 New Zealand dollars ($148USD)
or:
Silverstone ST60F 600W @ $250 NZD ($154USD)

PROVIDED I can fit it into my current case?
Or would 500-550W versions made by these manufacturers suffice, as they are quite substantially cheaper?
Cheers


get the silverstone PSU.And the 7800GTX 256 MB
August 1, 2006 2:29:04 AM

i always use antec power supplies but if you are lookin to upgrade to more power for less$$ and you dont mind waiting for a rebate here http://www.circuitcity.com/rpsm/oid/143299/rpem/ccd/pro... heres a good low price and specs should be ok.(had to get specs from ultra website) that should be fine for a while or next upgrade
August 1, 2006 2:29:14 AM

Sweet as. So the PSU will fit into my current case? Sorry to be a whiny nub, just wanna make sure :D 
August 1, 2006 3:00:03 AM

Is that a Sonata II case that you have?

That Silverstone is (180mm) 7 1/4 inches deep by (150mm) 6 inches wide and is 3 1/2 inches (86mm) high. You can take measurements based on those figures to be certain.
August 1, 2006 3:08:58 AM

Its a Thermaltake Soprano
August 1, 2006 3:13:10 AM

I edited my last message and left you with the measurements for the Silverstone PSU so that you could take your own measurements to see if fitting it would have any problems.
August 1, 2006 3:20:56 AM

cheers, thanks for that
!