Currently running a 300W PSU however i have just got some new parts.
They are as follows
Phenom II X2 550 BE
MA770T-UD3P
2GB DDR3
ATI HD2600 Pro
Old system is
Athlon XP 2500
MSI K7N2 someting
1GB DDR2
9600XT
Audigy Soundcard
Probably going to use the onboard sound on the new Mobo. Will i need a 400W PSU or do you reckon the 300W will do. Also is there anything wrong with the cheap PSUs? I see brand named ones sell for over twice the price for no apparent reason.
a good 500watt power supply would be fine for that system w/ plenty of headroom. I had my overclocked i7 rig running w/ a cheap 550 watt just fine, now i have a 780 watt power supply though.
I was told its best to have a power supply that is maybe only being stressed 50% under the full load of your system. so 500 sounds about right for that system?
Corsair's god a good reputation. ur suppost to look at teh 12v total wattage to determine if it is a good psu among other things. if the total down the 12v rail is close to the listed wattage of the power supply, that's supposed to be a good sign.
O.o 50% load only?
sorry but that sounds bust as i'm running 5 discs a ati 1900xtx and amd64 3700+ audigy fatality and 2 external usb dvd-burners (supplied by the pc-psu) under stress for hours with a PSU 350W.
The exhaust temps of the psu are barely warm...
I understand that correct energy-consumption assessment of modern computers is a very tricky part caused by harmonics on the Psu-net side.
But ridicule psu overhead of 50%(!) is just wasting way to much energy.
and what's the consequence?
YOU PAY too much for electric energy...
Hmmmm you pay what you use. If you put in a 1200 W supply and use only 400 W you pay for 400 watts you use. Gabbicks made a very valid point. you need headroom in your PSU. Offcourse he could power it with a 350 W supply but meaning its running at 80-90% load in use. That will kill the life time of the supply enormous. The supply is one of kkey ingredients op a PC. If that aint right you can have serious damage to hardware. Dont be cheap on a power supply because in the long run it will shoot ya in the face.
No, you'd just pay too much for the power supply. A power supply does not always use its listed wattage. It only uses what the computer needs. Thus, a 1000w power supply used in a computer that only needs 300 will indeed use only 300, the remaining 700w left being simply unused overkill. The role of the power supply is not, per say, to give the computer the power it needs. That's the role of the outlet. The power supply regulates the power given by the outlet, and makes sure it's safe for the computer to use (spikes, etc). The first thing checked when a computer boots is whether or not the PSU is ready to give the computer this safe power (power_good signal).
As for the OP, I'd say that a 300w PSU is probably enough for the system you plan to use. However, things could changed based a few things: other devices (Hdds, usb devices, cd/dvd/ray drives, etc), the age of the PSU (it weakens with time). Also, consider that a new power supply is an investment that gives you the opportunity to enhance your system without having to upgrade the power supply.
Personally, I'd buy a power supply with these things in mind:
- The power your computer needs (wattage, 12v rail);
- Possible overclocking in the future;
- Capacitor aging;
- Possible computer upgrade in the future;
- Cooling;
- Price
edit: good point, niels, having a PSU that is just enough power for your computer under load is not a good thing for the power supply. It'd be like having a car whose engine is barely enough for the weight of the car: the result is the engine is being stressed.
To maximize the power consumption of the computer, you want your PSU to be as efficient as possible. That is to say, that it wastes as less energy as possible. For instance, a 100W PSU that is 75% efficient will produce 75W, and dissipate the rest in heat.
I'm sure most of you have heard of the 80 PLUS certification that is found on a lot of PSUs. That means that the PSU is 80% efficient, on average. That is the average performed in tests, conducted as part of the the 80 PLUS program.The peak efficiency on the typical PSU is around 50-75%. That means that to achieve the best possible results for your PSU, you'd want your computer's typical power use to be in that gap of peak efficiency, most preferably at the peak efficiency of the PSU (though I do see this get easily tedious).
Therefore, I'd say that the best bet is to go for a 80 PLUS certified PSU, which will have a 80% efficiency average, and will thus be somewhere around 80% at all loads.
It is true, as micha said, that the efficiency drops at lower loads, so you wouldn't want to have a 1000W PSU with a computer that only uses, say, 300W of this. However, 80 PLUS PSUs remain quite efficient (mostly over 80%) at such load. It's just that to get the most out of the PSU, you'd rather stay around 50-60% load.
Attached is the power curve of a Corsair CMPSU-1000HX (1000W) observed at the 80 PLUS tests. You can see that it remains over 80% efficient over its load curve.
For the OP, to calculate the typical power use of your computer, we'd need more info (hdds, usb devices, anything that uses the PSU) to calculate the amount of power the computer uses. To be real picky, we could then see what's the most efficient load of the PSU, and from that see if the system and the PSU fit.
wow your real smart just go away you dont know what your saying. a psu like there saying with about 50-60% of the psu being used is going to be more efficient and will only use what the computer needs therefore it will not be more power from using a bigger psu but it will be less stress on the psu and less heat and thats the whole point of computers is less heat the better
he is right tho think about it the engine uses more gas so you dont want to have to much just sitting there it would be a waste of money if u really think about it...
you said it yourself, then why are there 1kw(!) Psus on the market?
The best thing would be a unit able to switch modules into the loop.
These modules produce say 25W at peak efficiency.
Beeing add up (parallel) to any desired demand.
(that's how large area power nets are supplied, with Dyn5 transformators in parallel switching, for example the net demands 3000 KVa, so you'd need either one 3000 KVa trafo or three 1000 KVa trafos)
If the load drops, some modules get completely unconnected, this way the overall unit efficiency stays up, wether the load is high or not.
But to get on topic again, nate, what's your hard evidence for telling me to go away?
This still wont raise your energy bill by using a large power supply.
Who ever gave you that idea. If his PC is using 400 watts in load condition he will pay for that. Not for the 1000 watts power supply he has or the 600 watts not used.
And the efficieny of a PSU aint that horrible anymore nowadays.
Surely you will gain more efficiency of the power supply if you have more demanding hardware but it wont drop that much as you say.
Old PSU wouldn't hook up to new mobo. Well the 20 pin would but the 4 pin wouldn't fit anywhere. So i wanted to get a new PSU with 24 + 8 rather than 20+4 however i was working today so got my dad to get one. The shop sold him a 20+4 600W and said it would work. Now this one fits fine however when i hit the power button the LED on the PSU lights up then dies and the cpu fan spins for a split second before stopping.
Nothing ever works first time for me and its really starting to piss me off. Especially since the shop i got it from is closed until the 4th of Jan.
The 4 pins and 20 pins connector should fit. Even if you dont occupie the full connector on the board it should run. Well it ran for the first time. The extra 4 on each connector are etxra power to the board. Which you use only to get more stable juice to the CPU for instances. Unless this board is really using those extra 4 pins it should work.
I would get a replacement PSU. I had a very similar problem recently. I would power up the computer, the fans would turn for about half a second, then it would die. The PSU was just unable to get good power to the computer (that's the first step in the boot process), and just shut down. The computer worked with another PSU.
So I would try to plug in the computer with the old PSU, with a basic setup (mobo, cpu, ram, graphics card) to see what happens. It works, then blame the new PSU.
About the 20+4 pin connector. You can plug a 20 pin connector in a 24 pins motherboard. The opposite is also true as the 20+4 connectors from PSUs are usually detachable into a 20 connector (hence 20+4 and not 24). The amount of power is the same in a 20 or 24 pins connector, the extra 4 pins are just there to remove a part of the stress on the other 20 pins.
The same is true about the cpu connectors. A 4 pin cpu connector can be used in a motherboard that has an 8 pin one. It's just that the 4 wires will be stressed more that way.
The mobo has a 24 pin power slot. I put the 20+4 into this. Then it has an 8 block slot. There is a 4+4 cable that fits in here although makes no difference.
The PSU is an AcBel iPower 660 which i just read a really bad review about. It is 610W so it should be more than enough to start. I only have cpu, ram and GFX connected at most.
Oh yes, I didn't mean otherwise. I just mean that it may be broken, in which case it's possible that it does not start. The best way to verify this is simply to try plugging in this basic system with the old power supply (it's only 300w, but simply to boot up to the bios, especially with a diminished system, it is alright).
What's this 4pin one you're on about? You sure that isn't the one that's ment to go straight into the 4pin slot which powers the CPU? Should work fine with just 20pins, you don't need to jam another 4pins in, something else is the issue.
Either you can just plug the 20 first pins, which should work, assuming that you leave the correct 4 alone (check in the mobo manual for this).
Or, the PSU comes with a 20+4 connector, which fits in the atx connector, assuming that the extra 4 pins are correctly attached to the 20 first ones. Do make sure they are, else they won't go in.
The cpu atx connector should be plugged in as usual.
There's no reason for the power supply not to work with this motherboard, if it worked with the old one...
Problem solved. Disconnected the fan that was in the case and hey presto system booted up. Only discovered this after spending money on a Corsair PSU and an HD5750! At least i got my money back on the piece of shit Acbel PSU even if it wasnt the problem.
So If i Put a 1,000 watt psu in a system, It'll raise my energy bill just from using a more powerful PSU?