Results 1 to 5 of 5

Thread: Is maximum wattage really important?

  1. #1
    Join Date
    Sep 2010
    Location
    localhost and Italy
    Posts
    316
    Thanks Thanks Given 
    11
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default Is maximum wattage really important?

    As title.

    I would like to understand if PSUs maximum wattage means something important.

    Suppose that I need to connect a SLI of GTX580.
    NVIDIA suggest a PSU with 60A on +12 rails and a minimum of 850W.

    If I have more than 60A on +12V with a 750W PSU am I ok or I need the maximum wattage of 850W?

  2. #2
    Join Date
    Jun 2009
    Location
    Montreal, Canada
    Posts
    1,734
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Based on nVidia's numbers, you only need a PSU with 60A on the +12V rails; not necessarily an 850W unit. However, their recommendations are generally conservative, so you should look up some actual power consumption measurements for that card done by a site like Xbit Labs which actually measures it directly, and base your estimates off of that information.
    Main: i5 2500K@4.6GHz w/Zalman CNPS10X Performa, Intel DZ68BC, 8GB G.Skill DDR3-1600, PNY GTX 470 + EVGA GTX 470, ASUS Xonar DX, ADATA S510 120GB, Samsung 1TB F3+1TB F1+2TB F4, Kingwin LZG 1kW, Lian-Li PC-9F, Dell U2212HM+S2209W, Win7 Professional.
    Laptop: Dell Vostro 3450, i5 2410M, 8GB DDR3-1333, AMD Radeon HD 6630M 1GB, Intel X25-M 80GB, Seagate Momentus 750GB, Win7 Home Premium.

  3. #3
    Join Date
    Sep 2010
    Location
    localhost and Italy
    Posts
    316
    Thanks Thanks Given 
    11
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Quote Originally Posted by Zero82z View Post
    Based on nVidia's numbers, you only need a PSU with 60A on the +12V rails; not necessarily an 850W unit. However, their recommendations are generally conservative, so you should look up some actual power consumption measurements for that card done by a site like Xbit Labs which actually measures it directly, and base your estimates off of that information.
    ok, so the only things I need to care is Amp, right?
    What do you mean for conservative? Do you mean that they say more than what is really needed?

  4. #4
    Join Date
    Jun 2009
    Location
    Montreal, Canada
    Posts
    1,734
    Thanks Thanks Given 
    0
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Yes.
    Main: i5 2500K@4.6GHz w/Zalman CNPS10X Performa, Intel DZ68BC, 8GB G.Skill DDR3-1600, PNY GTX 470 + EVGA GTX 470, ASUS Xonar DX, ADATA S510 120GB, Samsung 1TB F3+1TB F1+2TB F4, Kingwin LZG 1kW, Lian-Li PC-9F, Dell U2212HM+S2209W, Win7 Professional.
    Laptop: Dell Vostro 3450, i5 2410M, 8GB DDR3-1333, AMD Radeon HD 6630M 1GB, Intel X25-M 80GB, Seagate Momentus 750GB, Win7 Home Premium.

  5. #5
    Join Date
    Oct 2007
    Posts
    446
    Thanks Thanks Given 
    21
    Thanks Thanks Received 
    0
    Thanked in
    0 Posts

    Default

    Quote Originally Posted by sblantipodi View Post
    What do you mean for conservative? Do you mean that they say more than what is really needed?
    Often far more. It's a vicious circle: graphics card companies overspecify to allow for PSU crappiness, and PSU manufacturers overrate to use up that safety margin.

    It all started in the days of 5V-heavy PSUs. When the first serious video cards needed their own 12V supplies, PSU recommendations had to allow for the fact that the PSU's 12V rating was about half of its total rating. Cheap PSU manufacturers quickly started selling "500W" PSUs that were actually 12V-heavy 250W. And there things have sat.

    If you're not doing major overclocking, budget 200W for the CPU+motherboard and 200W for each GPU and you'll be fine. Then all you have to do is find a PSU that can actually deliver that power.

Similar Threads

  1. only 12V maximum capacity is important right?
    By Oliver Valdéz Guzmán in forum PC Power Supply Discussion
    Replies: 5
    Last Post: 08-11-2018, 10:10 AM
  2. psu maximum continuous power
    By OZSA in forum PC Power Supply Discussion
    Replies: 7
    Last Post: 08-06-2016, 06:47 AM
  3. Question about maximum wattage rating(s)
    By EvanWins in forum PC Power Supply Discussion
    Replies: 10
    Last Post: 06-05-2014, 04:37 PM
  4. 18AWG Maximum Safe Power
    By DuckieHo in forum PC Power Supply Discussion
    Replies: 6
    Last Post: 08-06-2008, 04:22 PM
  5. Maximum SATA drives
    By bonanza in forum PC Power Supply Discussion
    Replies: 3
    Last Post: 07-08-2007, 10:22 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •