24 or 20-pin Powersupply for new Sempron system

[whimsy]

I'm currently in the process of building a new PC for myself, and I've got pretty much everything but the power supply picked out, and I'm a little uncertain/nervous about this last bit:

First, I've already got an older ATX case complete with a used/useless ATX 235W power supply. (I expect to throw it out!)

I'm going to use an ASUS K8N-VM (http://www.newegg.com/Product/Product.asp?Item=N82E16813131588) motherboard (or very similar model) and probably a Sempron 2800+ The mobo uses the nvidia 6100 / nForce410 chipset with integrated graphics. I probably won't get a PCIe x16 video card, but could someday if needed--I'm not a gamer, I just run lots of apps and use lots of memory, with a 1GB DIMM (room for a second one if I need it later). Other power consumption will come from:
new SATA-II Hard Drive, 160~250GB
new DVD+/-RW DL drive
old CD-ROM
old floppy
Odds and Ends: PCI or USB2 wifi, modem, flashcard reader, keyboard/mouse

I've read saph's stickie about power supplies, and I'm a little uncertain, since all the PSU's listed have the 20-pin connector, and my motherboard has a 24-pin connector. The manual recommends a 300W (or more) supply, and at least 15A on the +12V supply (especially for a 20-pin connector)

I was looking for 24-pin dual +12V power supplies on newegg (http://www.newegg.com/Product/ProductList.asp?Submit=ENE&N=2010320058+70000541+70001490&Subcategory=58&description=&srchInDesc=&minPrice=&maxPrice=&ATTR2=&ATTR3=&ATTR4=&ATTR6=&ATTR7=2010320058+70000541&ATTR9=&ATTR10=). Here are a few that claim to have greater than 15A capacity on each +12V:

Sparkle 300W (http://www.newegg.com/Product/Product.asp?Item=N82E16817103514) $37 is cheap enough, but I'm not sure this will cut it.
Coolmax 500W (http://www.newegg.com/Product/Product.asp?Item=N82E16817159040) $63
Cooler Master 450W (http://www.newegg.com/Product/Product.asp?Item=N82E16817171001) $87, more than I think I want to spend

Should I get one of these, one of the 20-pin models, or a different 24-pin model? I'm not sure if the 15A@+12V is needed for both supplies with a new ATX12V 2.0 supply. I suspect that several of the supplies that don't spec the current would be sufficient, but it is hard to compare two units when only one has specs.

I don't particularly want a cheap/lame/off-brand/non-brand PSU, but I don't even know what a "good" brand of power supply is, having never cared when I built PCs before.

[pangea33]

You're missing out on more than 100 compatible power supplies by looking specifically for 24 pins connectors. There is also a connection type referred to as a 20+4 pin connector. These have 20 pin leads, as well as a detachable 4 pin lead to increase compatibility. They can be used on either motherboard type, and quite a few are offered in between the price range of the psus you've already mentioned.

Dual 12v psus with 20 and 20+4 connectors (http://www.newegg.com/Product/ProductList.asp?Description=&MinPrice=&MaxPrice=&OEMMark=0&OEMMark=1&Manufactory=0&PropertyCodeValue=1313%3A9959&PropertyCodeValue=1313%3A10111&PropertyCodeValue=0&PropertyCodeValue=0&PropertyCodeValue=0&PropertyCodeValue=2954%3A18939&PropertyCodeValue=2954%3A18938&PropertyCodeValue=2301%3A13789&PropertyCodeValue=0&PropertyCodeValue=0&Submit=Property&SubCategory=58)

Dual 12v psus with 20+4 pin connectors (http://www.newegg.com/Product/ProductList.asp?Description=&MinPrice=&MaxPrice=&OEMMark=0&OEMMark=1&Manufactory=0&PropertyCodeValue=1313%3A9959&PropertyCodeValue=1313%3A10111&PropertyCodeValue=0&PropertyCodeValue=0&PropertyCodeValue=0&PropertyCodeValue=2954%3A18939&PropertyCodeValue=2301%3A13789&PropertyCodeValue=0&PropertyCodeValue=0&Submit=Property&SubCategory=58)

[whimsy]

You're missing out on more than 100 compatible power supplies by looking specifically for 24 pins connectors. There is also a connection type referred to as a 20+4 pin connector. These have 20 pin leads, as well as a detachable 4 pin lead to increase compatibility. They can be used on either motherboard type, and quite a few are offered in between the price range of the psus you've already mentioned.
Let me see if I got this right:

20-pin -- OLD ATX
24 pin -- New ATX
20+4 pin -- hybrid connector that fits either of the above

And The extra +12V connector is in addition to whichever of these I choose, so I need a Dual +12V with either 24 or 20+4 pin connector to power my mobo.

(See! I said I didn't know squat about PSU's!)

[pangea33]

Let me see if I got this right:

20-pin -- OLD ATX
24 pin -- New ATX
20+4 pin -- hybrid connector that fits either of the above

And The extra +12V connector is in addition to whichever of these I choose, so I need a Dual +12V with either 24 or 20+4 pin connector to power my mobo.

(See! I said I didn't know squat about PSU's!)
I only know this stuff because I've recently been researching it myself. No one knows everthing to start with. You're right regarding the pin outs, but I think you might be slightly confused about the dual 12v power rails. This simply means that there are 2-12v supply rails inside the power supply, in case one can't keep up with demand.

Externally, you still just hook everything up like you did with older psus. There isn't actually an additional 12 volt connector coming off the power supply. The total 12v current rating can be found by simply summing the capacity for both rails. Your summary is essentially correct though, you want "a Dual +12V with either 24 or 20+4 pin connector to power my mobo."

Here is a good article about the ATX12V 2.0 specification from Tom's Hardware: http://www.tomshardware.com/2004/12/23/more_performance/index.html

[whimsy]

You're right regarding the pin outs, but I think you might be slightly confused about the dual 12v power rails. This simply means that there are 2-12v supply rails inside the power supply, in case one can't keep up with demand.

Externally, you still just hook everything up like you did with older psus. There isn't actually an additional 12 volt connector coming off the power supply. The total 12v current rating can be found by simply summing the capacity for both rails. Your summary is essentially correct though, you want "a Dual +12V with either 24 or 20+4 pin connector to power my mobo."Geez, now I'm even more confused. I read the Tom's article, then the manual for the ASUS board;Here is a section from the manual to the motherboard saying how to connect the power supply:
8. ATX power connectors (24-pin EATXPWR, 4-pin ATX12V)
These connectors are for an ATX power supply....
We recommend that you use an ATX 12 V Specification 2.0-compliant power supply unit (PSU) with a minum of 300 W power rating. This PSU type has 24-pin and 4-pin power plugs
If you intend to use a PSU with 20-pin and 4-pin power plugs, make sure that the 20-pin power plug can provide at least 15A on +12V and that the PSU has a minimum power rating of 300 W....
Do not forget to connect the 4-pin ATX +12V power plug....
You must install a PSU with a higher power rating if you intend to install additional devices.I guess I need a 24-pin or 20+4 pin connector for this mobo.

Now I'm 90% sure that the 12V 4-pin connector is a standard one that most decent power supplies now have, so I don't have to worry about that.

And I guess that the +12V @ 15A requirement means that with dual +12V1 and +12V2 needs to add up to over 15A.

Have I finally figured this out now?

[pangea33]

Forgive me for introducing that confusion, as I was mistaken. These power supplies do have an additional +12V 4-pin connector to support the P4's power requirements. My AMD doesn't require this, so there is no 4-pin socket on my motherboard. It seems pretty obvious that this standard will always have that plug on the psu.

The 4-pin plug of the 20/24 connector is indeed different from the P4 plug, and your first comments were right.

*punches self in head* :eek:

[whimsy]

Yeah, but if you hadn't said it, I wouldn't have figured out that the ALL seem to have the extra +12V 4-pin connector. Thanks!

[whimsy]

So...now that I know that I can just get a fairly normal modern PSU....does anybody have a recommendation on power? I listed the drives in my first post. I figure that 300W would be marginal, and am guessing that around 400W will handle reasonable stuff.

I don't need the reserve capacity for six drives, and a HOT graphics card....I expect I'd need to upgrade more than the PSU to get that working on my system.

[DrKaufman]

Yeah, 400W should be enough for everyday stuff, but if you're going to upgrade to a "hot" graphics card you're going to need something with a bit more kick, around 500W or so. Try to get as much as many watts as you can now, even if you don't think you'll need it. Too much is better than not enough.

[Paul Komski]

Dont ever get hung-up on having 20 or 24 pin sockets since you can get converter cables in either direction; eg http://www.xpcgear.com/20to24pinatx.html