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How do you know how much power you need?

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August 21, 2007 12:42:10 AM

How do you know exactly how much power you need? These are the parts I am going to buy:

CPU: Intel core 2 duo E6750 @ 2.66 GhZ
Motherboard: Gigabyte GA-P35-DS3R Socket 775 Intel P35
Video Card: eVGA 8800 GTS 320 MB
RAM: OCZ Gold XTC PC2-6400 2GB 2X1GB DDR2-800 CL5-5-5-12
Usually: 2-4 usb devices
Hard Drives: 1 S-ATA, 1 IDE, and sometimes 1 external Sata
Floppy
DVD-RW Drive
CD RW Drive

Thanks.

More about : power

August 21, 2007 1:34:57 AM

Take a look at the Corsair 520 or 620hx models, and/or the Antec NeoHE 500/550 etc line of PSU's.

I ordered a similar system recently (slightly higher power needs) with the Antec 500w and it's fine from what everyone says.. haven't actually got the parts yet though, lol.
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August 21, 2007 2:34:13 AM

It says 340 W which is SO LOW, and that is a pretty high-end system. Why are people then buying 600W 800W and even 1200 W PSUS!!!
i imagine with SLi won't even be double 340W.
August 21, 2007 3:21:21 AM

Yup, 340 watts does sound about right for that rig.

People tend to overestimate for various reasons, but that some people tend to overestimate by too much.

Personally, I like to overestimate by 25%, to account for possible upgrades, as well as for aging in the psu. Also, most psu's tend to be at max efficiency at 75% load, rather than at 100% load. Only loading to maximum of 75% of the PSU's capability will also extend the life of the psu because it's not being pushed.

A good quality 500-550 watt psu with decent 12v supply would do you good for that system, unless you intend to overclock or water cool. If that is the case, then I would recommend a 600 watt psu.
August 21, 2007 3:46:26 AM

I just used the site to calc a system that I am designing.

Look at future proofing your system for any possible add on's that might take place. For example, there is no way I am adding a BlueRay drive to my system (at the present time). But some day I might. I use the site to determine that a Blue Ray drive would need 32w. Adding an extra internal HD for data backup would need 21 w.

Suddenly my projected system which needs 406w today might need 459w tomorrow. And those are reasonable upgrades that I can project that I might want or need.

Then there is the aging of capacitors. Oh, and how about maxing out the CPU to 100%. Suddenly I have spec'd out a computer needing 530w.

For me, buying a computer system with 450w PSU is not a good idea. 500w would be better. Anything over 600w is going to be overkill.

By the way, I just spec'd out a mom and dad basic computer, it only needed 237w. Dell & HP are selling the same specs with a 300w PSU. Goes to show that not every body needs 1200w PSU.
August 21, 2007 4:40:43 AM

Yes the currrent is important. I'm thinking of going for 600 W. Assuming a 500W PSU I buy it will:
- face resistance
- I will overclock
- Possible upgrades

Let's round that 370 W to 400 W of use. 400W of 600 W is about 66 percent use when maxed. Is that a good estimate or am I going too high? In terms of futueproofing, I heard that PCI-e 2.0 have a special 4-pin connector, so I really have no choice.

As for the amps, what's good? I did a LOT of reading today and it seems like a good PSU has two 12V volts, each with about 20 amps is good?
I don't know how much I need in terms of 3V and 5.5V since most of the system utliizes 12V. Help would be appreciated
August 21, 2007 6:15:47 AM

I got 422 when I did it
August 21, 2007 6:23:49 AM

This one is on sale direct from PC Power & Cooling for $119.00. Newegg has it at 149.99 on sale from $199.00. It is tier one and stomps the Antec and any PS in it's price range. Yes I know the Antec is cheaper. The 610 also has a single rail with 49 amps, so the whole 12v amperage concern disappears.

Silencer® 610 EPS12V Power Supply

August 21, 2007 3:08:41 PM

i thought it was better to have two 12v
August 21, 2007 3:29:05 PM

not neccesarily, it's just that single rail PSU's used to only come in relatively low amperage on a single 12V rail... adding a second 26A 12V rail is the cheapest way of adding 12V power, but you have to pay attention to which 12V connectors you attach to what components

e.g. you should have your Motherboard on one rail and your graphics card on the other rail to prevent overloading - since graphics cards get some of their power from the mobo connector anyway, if you used a molex to PCIe adaptor to attach to your graphics card, you could end up overloading your 12V1 and have hardly anything hanging off your 12V2

having a single 40+ 12V rail means you don't have to pay attention to which PSU connector goes on what components, and is a more robust solution
August 21, 2007 3:38:10 PM

yes you're right. Less confusion. I heard they had to follow some ATX12V guideline or somethin like that, that doens't matter right?

Well I could connect my video card to 1 12V rail, and the other to my CPU and mobo but ya, I know what you mean.

WHat abut the combined 12V. IF I have a single 12V rail with 40A, will the max be even close to 40A?
August 22, 2007 2:46:22 AM

A single rail is easier to deal with versus multi-rail. Many manufacturers are going back to single rail types.

Forty amps is about what you would need and still have the headroom you probably would want.

Reading your previous posts, you rounded your wattage number up to 400, then the 600 was 33% more. You should remember that overclocking stresses components and pulls more power from your psu. Having that extra amount would be very good to have when you overclock. I would think it would be a wise investment to get a 600 for overclocking, just as I had stated in my previous post.
August 22, 2007 3:10:13 AM

Yes I will overclock. Thanks I will look towards 600W. Will 700 or 650 be an overkill?

Also just checked out that the Geforce 8800GS requires 26 A of 12V.

My C2D CPU will be overclocked from 2.66 GHZ to 4GhZ. Will that be too much?
August 22, 2007 3:46:02 AM

yes i will be, or somewhere near that
August 22, 2007 3:57:38 AM

a single rail is much more convenient, but I just realized that should something go wrong, everything connected to that rail will be fried or damaged. What is the likelihood of something like this happening?
August 22, 2007 4:58:10 AM

does that cover the parts they might destroy LOL
a b ) Power supply
August 23, 2007 3:51:44 AM

crazlunatic said:
How do you know exactly how much power you need? These are the parts I am going to buy:

CPU: Intel core 2 duo E6750 @ 2.66 GhZ
Motherboard: Gigabyte GA-P35-DS3R Socket 775 Intel P35
Video Card: eVGA 8800 GTS 320 MB
RAM: OCZ Gold XTC PC2-6400 2GB 2X1GB DDR2-800 CL5-5-5-12
Usually: 2-4 usb devices
Hard Drives: 1 S-ATA, 1 IDE, and sometimes 1 external Sata
Floppy
DVD-RW Drive
CD RW Drive

Thanks.


Your video card pulls 26A on a 12v rail stock, O/C'd would pull even more its recommended to be powered by a 400w P/S I like to be above recommendations because I O/C my CPU and video cards, so I recommend this P/S for your system.
August 23, 2007 4:42:34 AM

video card doesn't pull 26a, 26a is the recommended minimum for the whole system with a 8800gts. card itself will pull less than 10 amps, since its tdp is around 120w and it uses other rails as well. the silencer 750 is overkill for his system, the silencer 610 is probably the best fit.
!