blowmedown Posted March 2, 2012 Share Posted March 2, 2012 My system: i5 2500k @ 4.2 6970 @ 950/1425 Z 68 MB 3 x 64 GB SSD's 2x CB 1TB HDD's 8G Ram Corsair H100 Liquid CPU cooler 5x 110 CFM 120mm case fans running at 100% with fan controller. How many watts do you think this system is pulling at idle and under load? I just got my P3 Kill A Watt usage monitor and for everybody that thinks this needs a killer PSU your wrong. IDLE 89 Watts Under load Prime95 and MSI Kombuster running at the same time CPU was at 100% GPU was at 99% it used a whopping 311 Watts Link to comment Share on other sites More sharing options...
HanoverFist Posted March 2, 2012 Share Posted March 2, 2012 (edited) My system: i5 2500k @ 4.2 6970 @ 950/1425 Z 68 MB 3 x 64 GB SSD's 2x CB 1TB HDD's 8G Ram Corsair H100 Liquid CPU cooler 5x 110 CFM 120mm case fans running at 100% with fan controller. How many watts do you think this system is pulling at idle and under load? I just got my P3 Kill A Watt usage monitor and for everybody that thinks this needs a killer PSU your wrong. IDLE 89 Watts Under load Prime95 and MSI Kombuster running at the same time CPU was at 100% GPU was at 99% it used a whopping 311 Watts i5 2500k @ 4.4 6850 @ 850/1150 MaximusIV Gene-z 1x 1TB SATA HDD 8G DDR3 1600mhz Ram Corsair H80 Liquid CPU cooler 4x 90 CFM 120mm case fans running at 100% with fan controller. Mine idles at 110. And max is 349/350 watts. Originally got an 800 watt Kingwin with aspirations for crossfire, but meh. So now i's just overkill. A 450ish watt would have been better for me. Edited March 2, 2012 by HanoverFist Link to comment Share on other sites More sharing options...
outsidermatt Posted March 2, 2012 Share Posted March 2, 2012 (edited) Yeah, people massively overestimate psu requirements. I'm running the following off of a 700w psu: i5 760 oced to 4.2 ghz(50% oc) a pair of 470s in Sli oced to 749/1625(30% oc) 8 gb ram 60 gb ssd 4x 3000 rpm fans 3x 1800 rpm fans dedicated sound card I haven't got a killawatt, but when I built this rig my napkin math suggested I could squeak by with 550w. I went with the 700w because it was on sale, and to give me a little bit of head room. Short of overclocked Quad Sli rigs and the like, I don't get the point of the 1000w+ psus. People just like big numbers, I guess. Edited March 2, 2012 by outsidermatt Link to comment Share on other sites More sharing options...
blowmedown Posted March 2, 2012 Author Share Posted March 2, 2012 (edited) i5 2500k @ 4.4 6850 @ 850/1150 MaximusIV Gene-z 1x 1TB SATA HDD 8G DDR3 1600mhz Ram Corsair H80 Liquid CPU cooler 4x 90 CFM 120mm case fans running at 100% with fan controller. Mine idles at 110. And max is 349/350 watts. Originally got an 800 watt Kingwin with aspirations for crossfire, but meh. So now i's just overkill. A 450ish watt would have been better for me. Same here i bought a corsair TX 850 Just did a test on my wife's AMD II x2 270 with a 6770 and got a big 189 watts under load i could of used the Antec NEO ECO 520 i put in it in my system lol. Edited March 2, 2012 by blowmedown Link to comment Share on other sites More sharing options...
hurriedcorgi Posted March 2, 2012 Share Posted March 2, 2012 Only reason I use an 800w is because it was on sale - guess it's nice to have the head room though for when the system ramps up it's power usage. Link to comment Share on other sites More sharing options...
Ansultares Posted March 2, 2012 Share Posted March 2, 2012 Only reason I use an 800w is because it was on sale - guess it's nice to have the head room though for when the system ramps up it's power usage.Or the psu ages. Link to comment Share on other sites More sharing options...
Gungan Posted March 2, 2012 Share Posted March 2, 2012 (edited) Psst.. Even though a power supply says 500W, it's really only 80-90% of that, and that's if it is a really good PSU. A PSU not certified 80 GOLD outputs 75-80% of its rated value or less. On a single mid range video card, you likely won't need more than 500 W. On a single above mid range card, up to 600 W is common. On a single bleeding edge cards you wanna start with 700 W. If you want to run SLI/Crossfire, the typical formula for determining how much more power you need is: VCard_Power_Req*0.65*2 (or 3 for tri-SLI). Assuming your card requires 30 (peak) amps on a 12 volt rail (like the GTX 560 Ti), that'll be 360 W for one card , so you'll need 468 W just for video cards in SLI, or 108 W more jumping from single to SLI with a GTX 560 Ti. It is unlikely that the rest of your system will draw 150 W unless you're running multiple hard disks and optical drives. Edited March 2, 2012 by Gungan Link to comment Share on other sites More sharing options...
Malastare Posted March 2, 2012 Share Posted March 2, 2012 I just got my P3 Kill A Watt usage monitor and for everybody that thinks this needs a killer PSU your wrong. IDLE 89 Watts Under load Prime95 and MSI Kombuster running at the same time CPU was at 100% GPU was at 99% it used a whopping 311 Watts Good PC builders have known this for a long time. Instead of getting a 1000W PSU, get a good quality 500W*. You are almost guaranteed to get better efficiency, lower temperatures, better reliability, better overclocking, and less wear on your components. Of course, a large number of video card manufacturers list drastically inflated PSU requirements, often because many people buy crappy PSUs and blame damage/poor-performance of their video card on the video card manufacturers. [*] Assuming that the actual peak power draw doesn't exceed 500W. Link to comment Share on other sites More sharing options...
Skoobie Posted March 2, 2012 Share Posted March 2, 2012 A higher watt PSU will use less of itself to push out the required voltage. So, for example, a 450W will use more to push 300W then a 650W will. In theory, this will make the larger PSU last longer. It also conserves energy. Link to comment Share on other sites More sharing options...
Harden Posted March 2, 2012 Share Posted March 2, 2012 I use a Cooler Master 450W PSU Bronze Certified 80%+ and it runs my system fine. I have in there. AMD APU A6-3600 Sapphire 6570 PCI-Ex16 12GB DDR3 10600 Ram 2 7200 SATA HD's (300GB & 1TB) SATA DVD Dual-layer Burner Link to comment Share on other sites More sharing options...
Toxen Posted March 2, 2012 Share Posted March 2, 2012 having a beefy PSU isn't so much so that you can run everything...it's so you can run everything without blowing the damn thing out. working in tech support, i'd say about 40% of desktop issues has to do with the power supply going out. Power supplies are not something you wanna cheap out on. Link to comment Share on other sites More sharing options...
Malastare Posted March 2, 2012 Share Posted March 2, 2012 Psst.. Even though a power supply says 500W, it's really only 80-90% of that, and that's if it is a really good PSU. A PSU not certified 80 GOLD outputs 75-80% of its rated value or less. No. Any reputable PSU reports its wattage as the maximum supplied power, not the maximum power draw from the wall. So, a crappy 600W power supply with 75% efficiency delivers (see note below) 600W to components, but pulls 800W from the wall. Now, this might come from a misunderstanding of efficiency mixed with a known misleading presentation of power. Just because a PSU claims it supplies 600W doesn't mean that it supplies 600W to any combination of components. The 600W maximum is usually the sum of the maximum power supplied across the 12V, 5V, 3.3V and -12V lines. These days, the bulk of the power is available on the 12V line, but not all of it. My PSU (Seasonic X650, a very good PSU) supplies 125W across the 3.3V and 5V lines. Usually, this would mean that you only actually have 525W available on the 12V lines. It's not really a lie, because every good PSU advertises this on its label. Of course, there is another aspect that does lend a bit more credence to your statement. A lot of low quality PSUs are not actually capable of delivering the wattage they rate themselves for. They measure the wattage in a theoretical environment, and ignore the effects of trying to supply power at multiple voltages and the heat that produces. Now, any PSU worth the money you paid for it should be able to run at max load for quite a long time. So... Summary: No. A 600W PSU supplies 600W, barring various misunderstandings. Link to comment Share on other sites More sharing options...
Malastare Posted March 2, 2012 Share Posted March 2, 2012 (edited) A higher watt PSU will use less of itself to push out the required voltage. So, for example, a 450W will use more to push 300W then a 650W will. In theory, this will make the larger PSU last longer. It also conserves energy. That's not true... not as stated, anyway. Especially considering efficiency --which is one of the best ways of measuring heat and overall 'wear'-- having an appropriately sized PSU is far better than having an oversized PSU. PSUs do not have flat efficiency curves. Generally, they reach their peak efficiency at around 50% load, and trail off slightly up to 100%. However, they generally have their lowest efficiency up to 20%. Since your PC will probably spend most of its time idling, you want your idle usage to be at the best efficiency you can get. Examples: The PC quoted by the OP (much like mine) uses about 300W at load and 100W at idle. My Seasonic X650, an 80Plus Gold PSU, has 87% efficiency at 100W. The XFX Pro 1250W PSU has only 82% efficiency at 100W. At full load (for the PC: 300W), the X650 has 92% efficiency. The XFX Pro is at a respectable 89%. Either way: The X650 is running at higher efficiency and producing less waste heat than the XFX Pro. In the end, it is the waste heat that wears out electronics. Now, note that the XFX Pro 1250 is actually a really good PSU. Imagine if we had compared the X650 to a lower quality PSU. Edited March 2, 2012 by Malastare Link to comment Share on other sites More sharing options...
Aussiedroid Posted March 2, 2012 Share Posted March 2, 2012 I would recommend doing some google searches for Wattage Calculators .. will give you a more accurate idea. Always allow some headroom off course as some calcs may not be 100%. Always add 10-20% more. From what you have (simular to me) runs fine with around 600watts, but if you can find one with a few more watts it would be good say 700-800watts. With the higher wattage you may also get an additional rail to run power through which can provide better stability (ie run GPU off one, CPU and other HW off other). VERY IMPORTANT though, the brand and model of the PSU you choose. A cheap PSU can say 800 watts but really only pull stable power at much lower levels (or provide dirty power to hardware and result in failures). Seen many issues relating to poor PSUs where everyone beleives its fault hardware (ie mainboard, GPU or whatever) but was due to the 'included' cheap PSU added with the case. Do some research and find some recommended PSUs to suit your needs. I wont comment on brands because I havent looked into it for a while and dont want to mislead. Perhaps others can recommend something here for you. Good (very general) rule of thumb, if its a physically heavy PSU its probabily a good quality one. Link to comment Share on other sites More sharing options...
Dokiardo Posted March 2, 2012 Share Posted March 2, 2012 (edited) My system: i5 2500k @ 4.2 6970 @ 950/1425 Z 68 MB 3 x 64 GB SSD's 2x CB 1TB HDD's 8G Ram Corsair H100 Liquid CPU cooler 5x 110 CFM 120mm case fans running at 100% with fan controller. How many watts do you think this system is pulling at idle and under load? I just got my P3 Kill A Watt usage monitor and for everybody that thinks this needs a killer PSU your wrong. IDLE 89 Watts Under load Prime95 and MSI Kombuster running at the same time CPU was at 100% GPU was at 99% it used a whopping 311 Watts The wattage need was more of a past issue. The primary reason being what the 12v rails were capable of supplying the video card with. In general, a few years ago that is, the 12v rails capabilities (in amps) pretty much correlated with the wattage of said power supply. This is no longer really the case with more modern power supplies (still are, but most more than supply said rails with sufficient power regardless of the watts). Were you running enough instances of prime95 for all cores too? Under load should include hard drive access and any other drives running at the same time also, just to be more on top of the true max. Considering you're running 5 hdd's your wattage use would be much higher. The wattage use of HDD's vary widely, 2-20w. But consider it an extra around 100w in your system. In addition, the 6970 under full load pulls on average 181w, your i5 around 128w under full load. That is just the two components of your system. You're not utilizing your sound card, nor read/writes of drives and memory, HDD's SSD's. Edited March 2, 2012 by Dokiardo Link to comment Share on other sites More sharing options...
Dokiardo Posted March 2, 2012 Share Posted March 2, 2012 (edited) Psst.. Even though a power supply says 500W, it's really only 80-90% of that, and that's if it is a really good PSU. A PSU not certified 80 GOLD outputs 75-80% of its rated value or less. That is not quite what the gold/silver and etcetera standards mean. What you're reffering towards is the power efficiency rating. Quoted from wikipedia, 80 PLUS is an initiative to promote energy efficiency in computer power supply units (PSU). It certifies products that have more than 80% energy efficiency at 20%, 50% and 100% of rated load, and a power factor of 0.9 or greater at 100% load. That is, PSUs will waste 20% or less electric energy as heat at the specified load levels, thus reducing electricity use and bills compared to less efficient PSUs. Sometimes rebates are given for manufacturers who use 80 PLUS-certified PSUs. so, psst, you dont know what you're talking about. pps psst, read the above posts in reply to your post. They're correct. PPPS, look up electrolytic capacitor aging. In general, or as a rule of thumb, with extended use the psu will lose its initial wattage capacity. One should add % to their wattage needs if they plan to keep it more than 1 year, or when using high drain components. A good tool for calculating wattage requirements/suggestive: http://www.thermaltake.outervision.com/Power Edited March 2, 2012 by Dokiardo Link to comment Share on other sites More sharing options...
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