How much Power do I need?

Computer_Freak

Computer_Freak

Active Member
Hey guys

Ok well i got a Huntkey 500W PSU, but i am worried that it will not hold out with the upgrades i am planning... It is a cheapish brand, and 500W wont hold out. (if it was a better 500W, maybe it would)

I want to get a new PSU, but with future headroom (Crossfire/SLI, Nehalem, future GFX cards etc.)

My current rig is in my sig, but Im gonna get a 4870 aswell.

When Nehalems come out, I will upgrade to a full Nehalem computer (CPU, mobo, DDR3 Ram the works...)

And im going to OC.

How much power do i need.

I was thinking to get the corsair 750W, to keep the PSU running at 80% load instead of 100% and to have headroom. But the 650W is about $50 cheaper.

Do I really need teh 750W or will a full gaming rig (and future Nehalem Rig) be fine with 650W? Keep in mind i want to be able to crossfire/SLI future GFX cards aswell...

Thanks guys
 
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How much total current (amps) does it have on the +12v rail(s) and how many are there

check the sticker.
 
well if you're wanting to run SLI or Crossfire in the future with a fairly robust system then get the highest amperage/wattage QUALITY PSU you can afford. manufacturers i would shoot for are PCP&C and Seasonic. both very good companies.
 
bubblescivic said:
well if you're wanting to run SLI or Crossfire in the future with a fairly robust system then get the highest amperage/wattage QUALITY PSU you can afford. manufacturers i would shoot for are PCP&C and Seasonic. both very good companies.
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Seasonic is way overpriced here.

For the price of a 600W, I can buy an equivalent corsair 750W and more.

Im gonna get a Corsair. They are a very good make.

I dont trust online calculators. I tried the same system in two calculators and one came out to 600W and the other 700W. Quite a diference.

I think ill just get the 750W
 
bigfellla said:
Good choice.
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WHy though.

Cause 750W has nore juice and i can keep it longer?

750W will be at less strain?

650W cannot handle a top system?

650W is $50 cheaper aswell.

So basically i need a PSU that can handle 2 x 4870 in crossfire.

And any new tech that is thrown at it (GFX cards are the main consumers of power...
 
I think you have answered your own question havent you. List the two PSU's and i will contrast and compare them for you. The 750W Corsair is a quality built unit for many reasons. I can go into this further, but do you want me to compare the huntkey psu to the 750W Corsair, or another PSU?
 
Agreed, in fact i already have one. Computer Freak, specify your options and i will show you why the 750 is a good buy if you want.
 
I want these to be compared

Zalman ZM750-HP (modular, same price as Corsair TX750, but it has 4 rails (I feel one is better))
Corsair TX750 (compared to the Zalman, the only pro is the Reputation, warranty and the single rail...)
Corsair TX650 (cheaper, but will it handle the power needed?)


The Upgrades i want to get is:

Now:
1 x 4870 (later get a second one and CF it). I want it to be able to handle future GFX cards.

Later:
Nehalem CPU (when it comes out)
Intel X58 motherboard (For CPU)
4 x 1Gb DDR3 1333MHz RAM
2 HDD
1 DVD drive
Wi-Fi - PCI aerial
+ little extras (fans)

So how much power do i need?

P.S If i get a 4870, will my Huntkey 500W be able to handle the power needs until i get my PSU? My Huntkey has 2 Rails, one @ 15Amps, and one @ 18Amps
 
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I would strongly recommend against using a 4870 with your current PSU. Although it has a good efficiency (85%), it has very weak 12V rails (1 x 15A and another 1 x 18A). As this PSU is not a true multi rail design, it shares the same transformer. Under ATX design standards, the 12V+1 in this case is dedicated to the CPU. As your CPU is currently only going to draw 7W at most, this effectively traps the remaining 8W on the 12V+1 rail so that it cannot be used elsewhere in the system. Essentially this means that you only have 18A to run the rest of you 12V system, including your graphics card. You need 26A min, but I would recommend 28A for a 4870 on a system that will be upgraded.

You can view your current PSU specs here, however it is not going to handle a 4870 imo. http://www.huntkey.com/eng/bookpic/200612279422419792.pdf

As you can see, this is why major PSU manufacturers (e.g. Corsair, PC Power and Cooling) are moving towards dedicated single rail design, without 12VAC limitations, as the percieved benefits of the multi-rail marketting con, are outweighed by the ever increasing amperage demands of modern components. I diverge.


Ok on to the PSU's. The Zalman PSU is actually a Seasonic OEM unit, so it is a good quality unit regardless. There are however, reasons why the Corsair 750W is better than the Zalman - Corsair has a 5 year warranty (Zalman 3) and the Corsair uses solid polymer capacitors which gives greater life, and finally the Corsair provides a single large 12V rail.

In terms of the difference between the 750W and the 650W Corsair, to maintain upgradablity to your system, the 750W is the way to go, having enough amperage on the 12V rail to supply 2 x 26A (PCIe graphics), plus any other upgrades with reason.

hope that helps a bit.
 
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bigfellla said:
I would strongly recommend against using a 4870 with your current PSU. Although it has a good efficiency (85%), it has very weak 12V rails (1 x 15A and another 1 x 18A). As this PSU is not a true multi rail design, it shares the same transformer. Under ATX design standards, the 12V+1 in this case is dedicated to the CPU. As your CPU is currently only going to draw 7W at most, this effectively traps the remaining 8W on the 12V+1 rail so that it cannot be used elsewhere in the system. Essentially this means that you only have 18A to run the rest of you 12V system, including your graphics card. You need 26A min, but I would recommend 28A for a 4870 on a system that will be upgraded.

You can view your current PSU specs here, however it is not going to handle a 4870 imo. http://www.huntkey.com/eng/bookpic/200612279422419792.pdf

As you can see, this is why major PSU manufacturers (e.g. Corsair, PC Power and Cooling) are moving towards dedicated single rail design, without 12VAC limitations, as the percieved benefits of the multi-rail marketting con, are outweighed by the ever increasing amperage demands of modern components. I diverge.


Ok on to the PSU's. The Zalman PSU is actually a Seasonic OEM unit, so it is a good quality unit regardless. There are however, reasons why the Corsair 750W is better than the Zalman - Corsair has a 5 year warranty (Zalman 3) and the Corsair uses solid polymer capacitors which gives greater life, and finally the Corsair provides a single large 12V rail.

In terms of the difference between the 750W and the 650W Corsair, to maintain upgradablity to your system, the 750W is the way to go, having enough amperage on the 12V rail to supply 2 x 26A (PCIe graphics), plus any other upgrades with reason.

hope that helps a bit.
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Thank for the reply mate.

See the thing is, the only thing thats keeping me from the Corsair is the fact that it is not modular. And the corsair has lots of cable, and they are long (cable ties will clean it up, but its still not the same...)

i think Ill jus get the Corsair. Ill find a way to manage the cables...

Thanks again.
 
Yeh, its a problem, but you can tidy it up (i know i have one). I can take a picture if you want. Modularisation reduces PSU efficiency, so its somewhat a good thing.
 
A picture would be nice.

I think I will just cable tie them to the roof of my case. And wherever it can be hidden.

Thanks for the help mate. I REALLY appreciate it.
 
Can i ask, what case do you have?

It is very spacious.

Im planning on getting the Coolermaster Centurion 590. Spacious and keeps thing cool...


Thanks for all the help bigfella. It has really helped me. Thanks for your time.
 
I got the biggest case ever. Gutted out an ancient Compaq server that had a WTX case, Its like 15" x 17" lol, and after a bit of dremelling it was ready to take a normal ATX PSU instead of the 2 nonstandard ones it had before. Really nice, chunky steel construction, ive got 8 hdds in it atm as well as 2x 8800. Shame they dont make cases like that any more.
 
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