Confused about voltages

[mondschatten]

Hi. I am somewhat confused about the voltage requirements written about in the THG review and the Anandtech review on power supplies. If I am reading correctly, Anandtech's review states that AMD users really benefit from the 3.3V rail and that the video card takes its power mainly from the 12v rail. I got this from the review on the Antec TrueControl 550W page and the TruePower 330W page of the review.

However, THG seems to state that AMD chips take their power from the 12v rail and that the video card gets its juice from the 3.3v rail (this off the chart from the "Inadequate and Deceptive Product Labeling:
Comparison of 21 Power Supplies" review). These reviews are in conflict aren't they? Am I missing something? Admittedly, I do not know that much about this subject so it might just be me.

The reason I point this out is I have a P4 2.8 HT chip that I want to overclock to 3.06 or so, 512 of Hyperx Kingston memory (also intend to overclock this soon) and a Radeon 9700. So I am looking for a power supply that best fits this setup. It seems some power supplies are relatively weak on the 3.3v rails and strong on the 12v rails or vice-versa. I need to know which voltages I really care about. Any help on this matter would be greatly appreciated. Thanks.

 

[Crashman]

Older boards used the 3.3v rail for the CPU, RAM, and AGP. Newer boards use the 12v rail for the CPU because the CPU needs a certain wattage, and you can pass more watts at a higher voltage (the wires on the power supply limiting current). This is especially true of the P4, which has the "ATX 12v" four pin header supplementing power to the CPU's voltage regulator.

I prefer Fortron power supplies because they are high quality, inexpensive, and rated below their true output. For example, a 400W Fortron produces more power than an Antec 430W or Enermax 450W power supply. And Newegg carries the Fortron 530W unit (more power than the Antec 550W) for $75.

Once you have that much power, you won't need to worry about how much your CPU draws, because you'll always have excess. That power supply could power 2 of your processors and still have enough power for a 9800 Pro, 6 hard drives, and a few CD/DVD devices.

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[lhgpoobaa]

To avoid such issues its best to get a quality PSU, and get more Wattage than what you strictly need.

This ensures you have power to spare, you can handle future upgrades well and the PSU is working less hard, meaning it will last for longer.
A PSU running right up near its limit will pump out lots of heat, supply flakey/variable voltage and will likely burn out quicky.

So with pretty much all top of the line computers people here at toms recommend a 400W PSU from a reputable brand (My prefrences are Antec, enermax or Fortron)

<b>I am not a AMD fanboy.
I am not a Via fanboy.
I am not a ATI fanboy.
I AM a performance fanboy.
And a low price fanboy.
Regards,
Mr no integrity coward.</b>

 

[mondschatten]

Well, thanks for the explanations. I had been seriously considering the Super Flower 450SS PS and the Thermaltake W0014 480W. But, actually, your Fortron 530W recommendation changed my mind. I, too, was impressed with the Fortron reviews, but had thought they were an expensive brand. I just ordered one for $68 at Dealsonic.com, which is right about where I wanted to be pricewise. Thanks again.