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Power Supply Torture Test
An anonymous reader writes "With the latest batch of power hungry graphics cards, the PSU in your computer is more important than ever. If you're looking for a new power supply, check out this group test. They've tested 19 PSUs - some good, some bad and some downright explosive!"
Mirrordot link to Trusted Reviews power supply review
500GB of disk, 5TB of transfer, $5.95/mo
That page is annoying, it keeps jumping up and down while I'm trying to read it, because of that stupid javascript ad.
It's kinda silly anyway, the article's premise is that they got access to this $20,000 power supply testing equipment... A set of simple $10-$20 high wattage load resistors would have worked just as well.
A $1000 scope might help if you want to catch a load dump overshoot, startup transient, or ripple, but it looks like they aren't even concerned with such important specs of a power supply, specs that could burn our your system.
Anyway, some testing is better than no testing, which seems to be the norm for computer power supplies, so I am thankful that someone with access did these tests, but it would have been more useful if they had tested more than simply steady state load.
I've had enough abrasive sigs. Kittens are cute and fuzzy.
I was having consistent random crashes - the computer would suddenly reboot (all the way to bios, instantly) with no warning. The only clue was it happened most often when I was doing a disk-intensive task (which meant I had several crashes while the system was writing the FAT... BAD news).
For months I troubleshot all kinds of stuff, to no avail. New mobo, new processor, rearranged hard drives, reinstalled software, new network card, you name it - one step at a time, but no effect. The crashes continued.
Finally I happened upon some similar accounts of instability and they mentioned power supplies. I thought I was okay with a 300w supply and my Athlon. Nope. As soon as I replaced it, instant stability.
Some things to note about my experiences:
I upgraded to the Antec TruePower 430. It's an extremely quiet supply, even quieter than my processor fan, with a temp-controlled variable-speed fan and a second case fan molex connector that also is temp-controlled. It rarely runs above idle, but my case is always cool. That alone was worth the upgrade price.
I was loading the supply more than I had realized: I run dual graphics cards, two hard drives, and two CD/DVD drives. The crashes were apparently caused by the hard drives - it's apparently well-known (in some circles) that the highest instantaneous current draw in a PC is when the hard drive head starts to seek (lots of current is needed to get rapid motion and get the seek times down). So anytime I was doing a disk-to-disk operation - like a backup or CD burning - I was loading the power supply dangerously close to its limit. One step over the line, and the processor would hiccup. Boom, instant bad FAT table and a week of rebuilding.
Finally, this wasn't an overnight problem. I brought it on over time by adding things to my PC incrementally... hey, let's add another drive... hey, a spare graphics card... I can keep the case - it's working fine, right?
So word to the wise: get a GOOD power supply, and get one that's rated well ABOVE your expected average load. Pay attention to those current draw numbers on the hard drives; wattage alone doesn't tell the whole story, and small spikes can kill you.
--Brandon / Split Infinity Music
The Seasonic which made honourable mention is almost dead quiet. The entire inside is one large fan, the largest I've seen.
First - I spent the better part of 20 years designing military and aerospace switching power supplies and systems. Admittedly these toys were commercial products, but I think I'm qualified to say the following:
:) )- the latter is seldom accurate.
a) purely resistive loads are a poor model for PC load characteristics, as are purely constant-current loads. But the CC load is a tougher test.
b) transient line and load response (or lack thereof) can preclude operation at the steady-stete levels tested.
c) I just skimmed the article as it was loading strange, but I didn't note any specific cross-regulation tests. These types of tests may yield poorer performance measurements. They almost always do.
d) Testing to see if a PS will run at full load is not the same as seeing if it will START under FL. I didn't notice these tests. Likewise Starting at low or hi input is tougher that running at same.
e) we ps designers had an expression: Power supplies are like assholes - everyone has one and everyone thinks they're an expert. The former is true (some folks have two
OK - flame away. I'm gonna go eat lunch.
Cloned foods give the statement "We had that last week!" a whole new meaning.
The output power rating, which is what you need for operation, is based on a combination of the outputs that can be simultaneously loaded.
The efficiency of a power supply is also dependent on the load being used. For instance, the main regulation feedback loop probably has the highest efficiency and the other outputs have secondary post-regulators that require more background power to operate.
Power supplies operate from a 120 volt or 220 volt input AC wall plug/outlet and undergo some severe transients at turn-on and turn-off. Some of the supplies have automatic voltage sensing circuits to operate from either of these inputs automatically. Nearly all power supplies operate from an internal 340 VDC. This voltage has to start from zero and return to zero when unplugged. Most present power supplies have a keep-alive circuit to allow instant on from a standby condition. (The green wire on the output side.) Don't mess with the green wire with yellow stripe that is on the input side. That one is a safety wire for the input protection.
A WORD of CAUTION: Give your power supply a chance! Design engineers cannot anticipate and design in protection for all conditions and still give you a power supply you can afford. When you turn it off, wait 10 seconds before restarting so that capacitors can discharge and voltages can settle to stable conditions. You may never be able to make a power supply fail if you don't, but you will not be happy if you do. I have designed power supplies, purchased, and tested PC and custom power supplies. I have two bad hard drives from a system I bought from DELL last year. A friend could not tell that the system turned on (too quiet) so he pushed the power on/off too rapidly and too many times. Twenty years ago,my first computer suffered a power supply failure when I turned it off and immediately changed my mind and turned it back on.
Looking up HIPER in the UL database, HIPER has a few products listed, but none of them are computer power supplies. So that's a brand to avoid.
Consistently, every power supply with a valid UL mark passed. And every power supply that blew up lacked a valid UL mark.
UL tests power supplies by loading them up to their rated load at their maximum rated temperature and running them for hours or days. They also test for safe behavior if short circuited, overloaded, or overvoltaged. They're not concerned with power quality, just safety. The device must not blow up or catch fire, even after a single component failure.
Report phony UL marks to UL at 1-877-UL-HELPS (854-3577). They arrange for seizure at U.S. Customs, and catch about $12 million a year of hazardous components, which are then crushed.