Minimum PS 300/350/400?

I'm putting together a new computer and I'm trying to figure out what kind of PS to get. I've got:

XP1800
Millenium Glaciator
512 crucial ddr (2x256)
Gainward Geforce 3 Ti200
1 6 Gig HD
1 40 Gig HD
Audigy
1 aopen 20/10/40 cdrw
1 samsung 48x cdr
PCI modem
PCI ethernet card
Giga-byte Ga-7dx

I'll be moderately overclocking everything overclockable.
Would a quality 300-350 Watt PS be fine? I'd rather not spend the extra money if I didn't NEED to. I don't really know much about power supplies beyond the basics, so some more experienced veteran help would be most appreciated.


Cbone

Welcome to the Forums!
Next: my standard "If you haven't read through the Beginners' Guides yet, check 'em out here "

There are quite a few companies that make highly regarded psus, and I'm sure that others will post about them: I can't, because I am cheap.

I use cheap components where I can so that I can run a few computers; this can be a risk though, you don't know what you will get!

I have 2 300 watt psus that work great with my overclocked Athlons, and only cost about $40- of course I bought 3 of them!

The most important thing I've found is the 5v line needs to stay above 4.9 or so or stability suffers a LOT. Two of my cheapo psus run around 5.05 to 5.1v most of the time (XP 1800{[email protected]} and Athlon 1000@1300 and are rock stable.

The third drops to 4.8 when I jack up voltages and the oc, so it is in my PIII rig (and stable).

All I've seen says that there are some manufacturers that tend to have better results, but even they occasionally ship a power supply that is a bit low. Odds are better though.

There is a lot of discussion about similar issues in this topic. Hoot, our resident expert, advises that one should look at the combined 3.3 Volt + 5 Volt wattage when assessing the psu, rather than the overall wattage...

Look here:
http://forums.overclockers.ws/vb/showthread.php?s=&threadid=55208&highlight=combined

I got that part about the 3.3 and the 5 lines already. But what makes the 220 combined PS so much better than the 185 combined PS? If the max rating of both is 300, is there something lacking in the 220 one? Or has the 185 model got puffed up juice somewhere you don't really need it? I suspect the latter. I would assume that any PS sold in the States would have to meet some standard of measurement. Is there any way to determine what you need and what you don't other than by buying and trying? Naturally, I don't want to do that. A breakdown would be VERY helpful. Say with a likely range of what power will be sucked by what.

Cbone

P.S. I'm not new. I just reregistered because I haven't posted anything in forever and I forgot my login stuff. Thanks for the nice "welcome".

The combined rating is the maximum power output of the 3.3V and 5V lines together (combined). The total output of the supply is not simply the sum of the maximum power for the 3.3V, 5V, and 12V lines because these outputs share stuff within the power supply. (The other negative voltages are barely used and can be safely ignored.) I know they share the input transformer--not sure what else they share. The combined (3.3V and 5V) maximum power output is important because many, if not most motherboards use only the 3.3V and 5V voltages to power the motherboard, although some (Asus perhaps?) pull power from the 12V line and regulate down to 5V (and maybe 3.3V) on the motherboard. The 3.3V is mainly for PCI, AGP, and memory. (Someone please correct me if I'm wrong. I only know some of this.) The 12V lines are used for other components, such as disk drives, fans, etc, although drives still pull some power from the 5V line.
As for a way to determine what you need... I'm finding out that this is pure black magic or experience. There are charts that list the power requirements of typical components, but if you go by these charts you'll end up with much more supply than you need. The charts tell me I use 300W combined and 400W total, but the charts also note that you should have about 50% headroom, and a 450W combined/600W supply just isn't available or necessary. I'm just fine with a 500/250 for my dual athlon, but 300/200 wouldn't work. Best thing to do is take people's advice but buy a little more than the minimum. Just because a few people have it running on some supply doesn't mean you will. That said, you shouldn't have trouble finding an adequate, inexpensive supply for your rig, but I can't offer specific advice.

Combined 3.3 + 5 at 220 is better than 180. I wouldn't consider going with less than 350 total and 220 combined 3.3 + 5. My ps is 370/220. And, I'd make sure it's on the AMD approved list.

A 350 watt should support your hardware if it's a good brand, but I'd go for 400w if you're going to overclock much or want some expansion headroom.