Power Supplies and Usage

Remove all ads!

I'm currently running my pc on a 450W power supply. I know i'm going to eventually have to buy a more powerful one, but I was wondering if some of the local gurus could offer me some advice.

I have a mobo capable of 2 16x pci-e cards. I currently have a geforce 7900 plugged into one slot. I'm planning on plugging an older radeon x550 (draws power through the slot, no additional connectors are required for this card) into the second slot (for additional monitor support). Will this extra card bring my power supply to its knees? (i have two optical drives, one hdd, and a newish - not overclocked - cpu).

I remember seeing a chart online somewhere that allowed you to plug in the different components of you comp for a recommended power supply. But i forget where it was.

Oh, and if i plug in the other card and turn the power on, will i wreck anything? After all, the tried and true method of seeing if it works might make more sense than fishing around for numbers.

Thanks for any help!

[ May 14, 2007, 03:53: Message edited by: Celesialraven ]

 

PSU Calculators:
This one tends to get posted around fairly frequently, just remember to add 30% to get around what you should get.
Here's another, its a tad more limited in what you can enter, but returns a bit more info on what you should get.
I couldn't see the x550 on either (when did it come out btw?), so I'm not sure how useful they'll be, perhaps just use 'em to see how much room you have to spare currently.

 

The X550 is another of the several X300 through X600 retreads that ATI created using the Radeon 9600 silicon, with AGP scissored out, and PCI-e neatly implanted. The X600 Pro amounted to a 9600 XT, more or less, while the X550 was actually a duplicate, in just about everything, of the Vanilla Radeon 9600.

None of the 9600s draw a lot of current, and that remains true when they are in X*** form. The added current requirement amounts to next to nothing for a quality brand power supply. On the other hand, the majority of available power supply brands are pretty bad, and a typical (Chinese- made, mostly) "450 watt" unit is roughly equivalent to a quality brand in the 150 to 180 watt sizes.

 

They cant be that bad surely? A PSU with 80% efficiency is considered good, so that means a good 200w PSU is really a 160w PSU. So is a 450w = a 200w, we can assume its putting out 160w, or about 40% efficiency. Frankly, as bad as they are, they can be that bad. 60-70% efficiency maybe, but 40?

Lots of components are made in china anyway, so I really doubt the stuff they produce is as a rule inferior. Look at Xclio - they are produced by Channel Well Technologies who also make other well known name brand PSU's.

 

No so simple. It has to do with the 12 v channels. The 450 label is misleading. A 450 supply does not put out 450 raw watts. It is a total of watts divide over different voltages used by different devices in the pc.


The high end power units have 3 or 4 12 volt lines to power videocards in SLI or crossfire, using one 12 volt line for a single videocard. Yours most likely has 2 12 volt lines. Look at the label inside tha case and look how much the 12 lines have in true watts. Chaep ones have less power on the 12 volt lines and to much on the other voltages.

And believe me that the difference between a cheap one and a brand like Coolermaster, Antec, is huge. It is als more stable and produces less heat. A power supply is not something to "just put one in"
It also need overcapacity to stay stable. my geuss is about 25 %

My fahter had prblems with a cheap 400 watt supply. He only runs a 2800 sempron with one 512 ddr1400 simm and on board vga. He had a rare supply with only one 12 volt line.

So open the case and look which one it is. what brand. Every one has a label on the unit whit information. I have got 325 watt over my 2 12 volt lines. Only 325 watt for the graphic card motherboard and processor. It is a Coolermaster greenpower of 430 watts and cost around 90 euro.

I know this post does not answer the first question, but I made it to explain that you must not stare yourself blind on the 450 watt on the label.

And ofcourse correct me i I am wrong.

 

There are probably 50 to 60 assorted brand names for power supplies used in PCs, almost all produced in Asia. Those from Taiwan are better. There are fewer than a dozen PSU brand names that can be depended on for quality. I can name seven right off: Antec, Enermax, Fortron, OCZ, PC Power & Cooling, Seasonic, and Sparkle.

I have held a Powmax "500 Watt" PSU out of a Powmax (mainland China, I believe) case in one hand, and a 180 Watt Enermax in the other, and the parts in the lower wattage rated unit were better, and weighed more, than the one falsely rated as "500".

You can most definitely use weight to judge, and I am surprised that the Chinese factories haven't begun to include a lead bottom in theirs to pretend they contain quality components.

 

I know the 500 is a maximum that in all likelihood will never be reached. read this thing on efficiency and how it affects output, it matters big.

I used to buy cheapy PSU's, but with the PC I'll be buying soon it'll be good stuff - thinking a 520w Corsair HX modular, maybe 620w.

Of course, if I'm going for Crossfire 2900 XT's, I might need more!

 

I am wondering why you list Antec as a good PSU supplier, as it is known to have relatively high failure rates. Especially the SmartPower 2.0 series is a bad one (2 have failed for me as well). I would never buy an Antec PSU myself, they make good computer cases though. The Neo HE series have some incompatibility problems and a bit lower efficiency rates than some competing PSUs.

Some PSU failure rates: http://www.behardware.com/news/8550/power-supply-failure-rate.html
About NEO HE series: http://www.silentpcreview.com/article273-page5.html

 

Antec PSU's are made by another company, so in this day and age you need to find out who is behind the brand.

XClio isnt a well known brand, but their PSU's are made by channel well technologies, who also make popular name brand PSU's, and consequently their PSU's are relatively inexpensive but pretty good.

 

Of course they are, CWT manufactures some Antec PSUs as well, which are good, but unfortunately they also use some other not-so-good manufacturers.

 

There is a other factor. I have subscribed on a magazine that only test hardware sometimes into the extreem. in one of those magazine they took 62 PSU and tested then. I am not going to bore you with all the results. The test is a year old so many models have been replaced by new ones. I choose a Coolermaster Igreenpower430 based on the data of that test, based on sound and efficiency. It scored top notch in those two fields, and the power was enough for my pc.

But a similair PSU af the same brand, the 430 extreme power was cheaper but almost half as good.

And now for something completely different. I work in a warehouse and we have spare parts for carmanufactures. We ofcourse can buy stuff from our employer like cars. When a new car arrives it comes in different models with different means of propulsion like diesel, petrol or electricity. And now comes the punchline: they tell us of the record which models are better than others. And now it falls in perspectieve whit the PSU's

We do not know which one's are made where, but we can use information to figure out which one to avoid. To add in Antec defense: the neoHE 550EC scores top of the line. The smartpowers score less. again you cannot judge a brand on one model.

 

Hell Tal, a 1KW power supply doesn't drawl gasps anymore!

One other thing to consider....the wattage listed is usually the *peak* (read: maximum output at a given point) wattage. If manufactures printed the RMS values on the boxes, the numbers would be a lot smaller.