I this episode of TechBits, I provide a crash course in understanding power supplies: everything from multiple rails, to available connectors, to wattages and features. ULTIMATECOMPUTERS.NET COMPUTER BUILDING COMMUNITY www.ultimatecomputers.net MY BLOG (JUST RANDOM STUFF THAT I LIKE TO TALK ABOUT, MOSTLY WHAT I’M UP TO) http MY TWITTER FEED (FOLLOW ME ON TWITTER; THE FEED IS ALSO DISPLAYED ON THE SIDE OF MY BLOG) www.twitter.com MY YOUTUBE PROFILE (DUH…AND DON’T FORGET TO SUBSCRIBE!) www.youtube.com
Tags: Demystified, Part, Power, supplies, TechBits





#1 written by moonshiry August 25th, 2010 at 09:37
pretty close? i was planning for a 620 watt for
amd phenom II 955
Asus M4A785TD-V EVO
xfx hd 5870
4 gb ram
western digital 500gb black caviar hard drive
LG SATA 22XDVD RW
win 7 64bit professional
#2 written by yamum248 August 25th, 2010 at 10:36
Hey I’m building a new computer and I’m just wondering what PSU to get either a corsair 1000HX or a thermaltake toughpower 1200w or any other psu. Here are my specs:
4 SATA HDD’s running in RAID 5
12gb of ddr3 ram
Gigabyte x58-extreme
i7-950
Thermaltake Armour+ LCS (ps hooking up all fans and the LCS)
dvd/cd rw drive
ATI 5850
Thanks alot
#3 written by sciguy14 August 25th, 2010 at 11:20
should be fine
#4 written by alex14469 August 25th, 2010 at 11:27
Great video but I have a question, my psu only has 1 six pin pcie connector but the video card I want to get requires 2 of them, my psu meets power and current requirements but does not have enough adapters, is it safe to use 2 molex to 6pin for a long period of time?
#5 written by sciguy14 August 25th, 2010 at 12:23
correct
#6 written by IntegratedDerivative August 25th, 2010 at 13:01
I see. So there is no such thing as a “12v rail cord”?
#7 written by sciguy14 August 25th, 2010 at 13:26
rails are handled within the PSU. You don’t have to worry about plugging into a specific location on the PSU.
#8 written by IntegratedDerivative August 25th, 2010 at 13:46
So if I only have one 12v rail, where would I plug it in to? Would all the parts that require the 12v rail still receive the power, being as you can only plug it into 1 spot?
#9 written by MRKetter81 August 25th, 2010 at 14:42
Ah ok good. Dude you’re a life saver.
#10 written by sciguy14 August 25th, 2010 at 15:05
Assuming both PSU are rated to be 80% efficient, yes the 650 would be closer to that 80% value. However the difference would be very small, maybe a few cents a year on your power bill.
#11 written by MRKetter81 August 25th, 2010 at 15:51
Like that guy above.. if I bought a PSU with 650 with the same setup he has. Would I notice a difference in power consumption with the 800w since the 650 keeps it somewhat closer to peak?
Also thank you very much for your help.
#12 written by sciguy14 August 25th, 2010 at 16:41
Not necessarily, it all depends on the PSU… Efficiency does increase as you approach peak load. Just because a PSU can supply 600W doesn’t mean it is constantly supplying that much.
#13 written by MRKetter81 August 25th, 2010 at 16:43
Does efficiency increase with more than one Rail?
Also I’m worried about power consumption after load. I mean simply because it says 600 wattz doesn’t mean it’s using that constantly I hope? O.o
#14 written by skateer25 August 25th, 2010 at 17:12
k thanks alot for all the help!!
#15 written by sciguy14 August 25th, 2010 at 17:38
That’s cutting it pretty close. It should work, but it leaves no room for upgrades. Go for 800W
#16 written by skateer25 August 25th, 2010 at 18:20
would 650w be enough if i was running
core i7 920
EVGA x58
xfx hd 4890
6gb ram
westerndigital 750gb hard drive
Sony Optiarc Black 24X DVD+R
vista ultimate
#17 written by sciguy14 August 25th, 2010 at 19:00
The PSU utilizes power sharing circuitry that allows one rail to “donate” amperage to another rail if it is being taxed to too much. It should be able to handle new cards fine, depending on what else you have in your system.
#18 written by asus3571 August 25th, 2010 at 19:17
brother i gotta say this was the best video on psus ive ever seen just subed but i do have a / i just bought a corsairhx620 modular psu w/312vrails at 18a each the manual says it can garantee 50 to 100amp on the +12vrail how can this be and do you think this psu will handle the newer cards at load
#19 written by Zayras7 August 25th, 2010 at 20:01
lol glad to know I didn´t miss anything
great vid again, very helpful!
#20 written by greenhornet123 August 25th, 2010 at 20:11
Thanks great video
#21 written by sciguy14 August 25th, 2010 at 20:17
well it needs 25 Amps total, but it can also get some from the PCI express bus. And it can operate with with less than 25AMPS when not on full load.
#22 written by saudikid August 25th, 2010 at 21:14
like for example, a 8800gt needs 25AMPS each rain and it only uses 1 6-pin rain, if a psu has 4 +12 rails with 18AMPS each, woudlt the 8800gt only be getting 18amps??
#23 written by smartwarlord August 25th, 2010 at 21:30
honestly these two videos are your best and most informative videos, i’m sure the newer people to building PCs or just people who care about whether or not their power supply will burn their entire system up… (i’ve had a friend who had that issue..)
#24 written by sciguy14 August 25th, 2010 at 22:12
What do you mean each rail? A video has only one total current level that it requires. How you divide that up between rails doesn’t matter.
#25 written by saudikid August 25th, 2010 at 22:18
some GPU need like 30AMPS each rail. and some high end PSU only provide like 20 AMPS each….is that ok or bad?