PSU with high rating on +5v, +12V rails, low on 3.3V rail

[Z_oc]

PSU is manufactured by Channel Well Technology - model: ISO-500. It's a 420 watt model with combined +3.3v +5v = 220 watts.

The amp ratings for each rail:

+12V = 18.0A
+5V = 36.0A
+3.3V = 22.0A

The +12V and +5V rails look beefy - but +3.3V is lower than the 350 watt HEC I am using now (28A). It's lower than many PSU's I've seen.

You think the lower 3.3V will have a big difference in stability? I like the decent +12V and +5V rails. PSU is quite heavy and comes with a single fan.

CWT is supposed to be a good manufacturer, and I heard they make PSUs for Antec also.

Should I take this PSU or avoid it?

 

[ZachM]

The ratings don't mean much. PSU's can be rated on the high side or on the low side of what they put out. I would go with the Channel Well. I don't know anything about HEC though.

 

[Oklahoma Wolf]

This isn't my preferred line from CWT, but the ISO 420w should power a decent system. Overclocking may be limited though - this one isn't quite as beefy as my older 420w (my 3.3v is rated 28a, 5v is 40a, and my 12v is the same).

CWT does make PSU's for Antec, but Antec only uses the A series (Truepower) and B series (SL/Smartpower) to my knowledge. HEC has also made PSUs for Antec back in the days mine was made, but as far as I know those were all below 350w.

I would give the ISO a try if you already have one or have little choice in PSUs... I don't think the lower 3.3v rating will hurt anything. I've never seen it stressed on mine. However, I would also look at the Fortrons above 350w at Newegg - Fortron build quality is slightly better.

 

[Z_oc]

Don't have Fortron where I live - otherwise would have gone for it. Actually the model is ISO-500. I think the ISO series is the "budget" line from CWT - designed for the OEMs so that they can get a reasonably good PSU without spending too much; A and B series are more high end,

The 3.3V rail is use for specifically what device(s) - PCI and AGP cards?

 

[Oklahoma Wolf]

Don't have Fortron where I live - otherwise would have gone for it. Actually the model is ISO-500. I think the ISO series is the "budget" line from CWT - designed for the OEMs so that they can get a reasonably good PSU without spending too much; A and B series are more high end,

The 3.3V rail is use for specifically what device(s) - PCI and AGP cards?

The ISO's are indeed the bottom of CWT's lineup, but I've seen the innards of one and they don't look that bad. You could do a lot worse, anyway. The last time I looked it seemed CWT was setting up ISO as a subsidiary company just for the budget market.

CWT's quality control is still among the best though - I've worked with several of them, and even an 8 year old 250w is still going strong. Never had one fail yet. My 420w is almost 2 years old, and is holding up nicely.

AFAIK the 3.3 is mostly used for memory, PCI/AGP, and other mainboard components. Might be forgetting something though - I'm almost typing in my sleep at the moment

 

[Z_oc]

Thanks wolf, for all the info.

I'll try out the IS0-500.

 

[larrymoencurly]

C'T magazine said that an XP2400+ system used up to 14A @ +3.3V.

I don't think I've ever seen the insides of a CWT ISO model, but one of their cheapest models looked about as bad as current Powmax and had small filter capacitors and uncertified high voltage capacitors in the EMI filer.

 

[Z_oc]

A snapshot inside the CWT-ISO 500.

The capacitors are rated at 820 mF.

 

[Oklahoma Wolf]

Looks decent in there, but build quality is lacking compared to my older 420w. If this one's a dual fan it would explain the smaller heatsinks. The main filter caps are lower values also.

Not a serious heavy overclocking PSU, but still decent IMO

CWT has yet to make anything as low quality as Powmax (including the low end ones), but I still tend to recommend above 380w for them. Below 380w, they're pretty much just average quality on all model lines.

Edit: here's a pic from Mikhailtech showing what mine looks like - it's packed with circuitry (single fan): http://www.mikhailtech.com/articles/psu/cwt420/cwt420-05.jpg

 

[Z_oc]

Wolf, your older model definitely has more components and the sinks are much bigger. My one is actually a single fan unit.

 

[Oklahoma Wolf]

Yep... keep in mind though when I bought mine it was top of the CWT line before they started selling the A and B series seperate from Antec under their own name (ISO came later). Paid $105 Canadian for it. A friend of mine got the next one down from mine, a 375w model that's almost as crammed with components but has dual fan (mine was never offered dual fan, but it does have space on the temp controller board to add one).

Not sure how heavy yours is, but mine's starting to warp the sheet metal of its case a bit... I remember thinking when I got it the store must have sent 2 PSUs by accident

Edit: one more thing I forgot - all the CWT units I've used have run pretty warm in normal use, especially my 420w. Don't be too alarmed about the air temp from the fan unless yours starts blowing really hot.