Power Supplies - what should be minimum amperage be on each rail?

[Blues X]

edit: who would like some 'futureproofing'... and who wouldn't? that 'who' was a typo, Zoidberg style.

My ti4200 died in my Dell 8250, so I'm looking at video card upgrades.

Given all the thing I'm running in my system (two DVD drives, two hard drives, 4-6 usb devices, plus upgrading to 6600gt or 6800nu), I don't think my current stock PSU will work. It's right on the border of wattage requirements with a newer video card, but I would rather have some room for certainty.

And I would like room to upgrade later to a new mobo with SATA, PCI-E, etc.

So what level of amps should I consider as the minimum? And I'm guessing it's more important for amps on the 12v line, vs. the 3 or 5v lines. I ask because I saw some comparably priced PSUs with different amperages per line.

For example:
THERMALTAKE Silent Purepower W0014RU ATX 480W Power Supply
+3.3V@30A;+5V@40A;-5V@0.3A;+12V@18A;-12V@0.8A;+5VSB@2A

Antec TRUE430 ATX 430W Power Supply
+5V@36A, +3.3V@28A, +12V@26A, -5V@0.5A, -12V@1A, +5VSB@2A

The Antec has fewer amps on the +5 and +3.3, but more on the +12 (which is where I think I would need more amps).

In addition to this, I'm not sure if I should get an ATX 12v model. Isn't the main difference from the regular ATX just another 12v rail? If so, sounds like that would not be a bad thing.

Thanks for any info.

 

[Promethply]

You won't go wrong with the Antec Truepower series, and the quieter Truepower2 series with the ATX2.0 is already out on the market:

Apparently, for current PCs, the most important criteria when it comes to PSU is the total Amps on the 12V rail(s)

The Truepower2 has dual 12V rails with a hefty total Amperage, which will satisfy your 'futureproofing' requirement.

 

[Blues X]

So, in short:

more amps is better on the 12v.

Two 12v's are better than one.

correct?

The Antecs might be a bit out of my budget range, but I also don't want to go with the "cheapo" route for such an important component.

Are the Coolmax psu's a recommended brand? It seems like I've read good things about them here and elsewhere.

 

[YOyoYOhowsDAjello]

This XClio 450 is a great "budget" powersupply that's made by the same company as antecs.

EDIT: oh wait, you're trying to replace a Dell powersupply? Some of those are proprietary and a regular ATX powersupply might not work with the motherboard. I'm no expert on this, but you should find out what kind you need for that motherboard before you get a new PSU.

 

[Blues X]

I did check that already, and my Dell was bought after they stopped using the proprietary PSUs (at least on this particular model).

From everything I can see, it's a standard 250wt ATX supply. The Dell proprietaries have an additional power dongle, which mine does not have.

The specs for it are at http://support.jp.dell.com/docs/systems/dim8250/techov.htm#1105626. It's the same supply that's used in the 8300 models, which had Radeon 9800pro's as an option.

For a laugh, here is the Dell tech response to my question about upgrading the power supply and the video card (to either a 6800 or 6600gt):

Thank you for contacting Dell Technical Support.

Mr. Goins, I would like to inform you that following are the video card
fro ATIO and Nvidia that are listed as compatible with your system by
Dell :-

Part number# F0503 - ATI Radeon 9000 TV Tuner Card, Dimension
Part number# 0U896 - ATI Radeon 9700 Pro w/TV Out, 128MB, R300,
Dimension, UHMGA7
Part number# 5X005 - ATI Radeon 9700 Pro w/TV Out, 128MB, R300,
Dimension, UHMGA7, 2nd Source
Part number# 7T753 - ATI Radeon 9700 TX w/TV Out, 128MB, Dimension
Part number# 9P301 - MRMGA5, 64MB NV17, nVidia GeForce MX 420 w/ TV Out,
Full Height
Part number# 4N458 - UHMGA6, nVidia GeForce4 Ti 4600 w/ TV Out, 128MB,
NV25, Dimension
Part number# 4R306 - HMGA5, 64MB NV25, nVidia GeForce4 Ti 4200

**** Please note that you may not be able to locate the part number in
our online website, therefore I would request you to order the part with
our Spare Parts Department. They can be reached at: - 1-877-645-1322 or
1-800-357-3355.

I cannot guarantee you whether the video card that you are referring to
in your email will be compatible with the Dell system or not.

Also, Dell does not recommend upgrading of power supply as this might
have any effect on your system performance.

 

[Blues X]

That Xclio does look nice. And I had seen them recommended here on the AT forums before.

So that's definitely an option. Do you know if it has the PCI-e video card power connection? I know that I can use 2 12v's with an adapter if I have to in the future.

I haven't done a serious (more than 1 component) upgrade in a long time. I almost forgot how much work & fun this is.

 

[Promethply]

Originally posted by: IHateRequiredNicknames
So, in short:

more amps is better on the 12v.

Two 12v's are better than one.

correct?

The Antecs might be a bit out of my budget range, but I also don't want to go with the "cheapo" route for such an important component.

Are the Coolmax psu's a recommended brand? It seems like I've read good things about them here and elsewhere.

Yup.

I wouldn't recommend the Coolmax COOLMAX CX-400B, for example, because it only carries 18A on the 12V rail.

The XClio 450, as recommended by YOyoYOhowsDAjello's actually better since it has a total of 32A on its 12V rails.

 

[YOyoYOhowsDAjello]

Originally posted by: IHateRequiredNicknames
That Xclio does look nice. And I had seen them recommended here on the AT forums before.

So that's definitely an option. Do you know if it has the PCI-e video card power connection? I know that I can use 2 12v's with an adapter if I have to in the future.

I haven't done a serious (more than 1 component) upgrade in a long time. I almost forgot how much work & fun this is.

If your videocard needs a special connection, it should come with the adapter cable I think.

From this link it looks like it does. If the blue connectors are PCI-e like it says.

 

[Zepper]

Actually a single +12V rail is better than a split rail for flexibility assuming the total available amps are equal.
Split rail is strictly a safety thing. Just tell me you won't be grabbing the leads of your PSU while standing in a tub of water...
. And I'd like about 25A available on each of the three main rails.

.bh.

 

[Blues X]

Thanks for all the info. My decision will be a bit more educated now.

And now, on to the 'hot deals' section...