I've been looking at new power supplies (to replace my the one I've currently got because it's driving me nuts with it vibrating all the time and making a humming sound) and I just can't make my mind up , so i'm hoping someone can help me out here . I looked at this one first 650w Silverpower-(Seasonic)-SP-SS650HT which looks like a fantastic buy at £64.96 Inc VAT Then I looked at this one 750W-TX-Corsair-PSU-single-12V-rail-quiet-and-cool-80plus-Eff £89.70 inc VAT almost £25 more expensive but 100 watts more powerful Basically it will be running the below so will 650 watts be enough if I went for the Silverpower one? i7 860 @ 2.80 ghz 4gb ddr3 1333mhz ram 3 Sata Hard Drives 1 Sata DVD Drive 1 IDE DVD-RW Drive 2 120mm fans one at the front and one at the back (one of them is L.E.D) gtx 275 graphics card And if I went for the 650 watt power supply, what scope would I have powerwise if I was to upgrade in the future? Also I have a tower case where the psu sits at the bottom of the case with the fan facing upwards, and I have a query about that, usually when psu's are at the top of the case the fan is facing downwards right, so if it's facing upwards doesn't that actually limit it's lifespan because dust is able to fall straight onto/into it when the pc is switched off, where as if it was facing downwards no dust could fall into it, or doesn't it actually matter? I have no idea, just thought I'd ask here because it saves making another thread
I've been surprised by how little seemingly power hungry systems use... This may help your descision Using this site I found out mu Akasa 400W PSU could easily handle all of the upgrades I have planned in the next year. some of which include an AMD Phenom II X4 955 CPU and the Radeon HD5850 GPU EDIT: My Antec300 case also has that PSU placement configuration, although I've not had it long enough to notice any possible major effects of the issue you noted, the PSU fan is an intake, so when turned on, it blows any dust inside the PSU out the back of the case
1) 650W will handle that system, no problem. If you ever wanted to step up to SLI/Crossfire, though, you'd want something with a little more in reserve (like an 850W). ...well, no, that's not the whole story. 650W could handle the majority of dual-card systems, but it would be pushed right about up to its maximum capacity (like in the 600-650W range), and it's not a good idea to run a PSU that way for extended periods of time. 850W would allow you to run at ~70-75% capacity, which is perfectly healthy. 2) Fan orientation only alters component lifespan in very specific situations. Generally, the big rule is that it's better to not run sleeve-bearing fans in vertical orientations (i.e. the fan blows air horizontally) because it can wear down the bearing more quickly, but ball-bearing fans are okay either way. Unless your PSU has a sleeve-bearing fan and you're turning it on its side (which you aren't), you don't need to worry about that, though. Dust, too, is only an issue if it gets in the way of airflow, but changing your PSU from case top to case bottom makes absolutely no difference. It may be easy to think that case bottom would allow more dust to get inside it, but keep in mind that dust only gets inside it anyway because fans are blowing air through the case; when your PC isn't on, no more dust gets inside. And when it is on, the PSU fan is forcibly pushing air through the PSU, no matter what way it's oriented. If you're really that concerned about dust, stretch some pantyhose over your intake fans. - Diosjenin -
The first thing to know about PSUs is that quality is more important than quantity. Seasonic are a good make as are Corsair though they don't make their own PSUs. I believe that the TX series are made by GMC (IIRC) who make PSUs for loads of companies, and the HX series (except the HX1000w) are made by Seasonic. I have a HX620w (Corsair) running my dual CPU, Dual GPU rig and its perfect, rock stable and very quiet. Moriquendi
I completely agree that it is not good to run a PSU up to its rated value for extended periods however running dual graphics cards may not necessarily be beyond a 650W psu depending on the card. The new 40nm GPUs, in particular, are very economical. Even many 55nm GPU would struggle to draw much more than 500W. Of course that does depend on the other components in the system.
