Discussion in 'Asus' started by grylion, Nov 24, 2011.

  1. grylion

    grylion Guest

    To start with thanks to Paul who gave me plenty to think about.
    original post below.

    new post below

    I have had a rethink about the system and realise I had fitted a sound
    card in later on because the onboard one went a bit flakey

    I am considering swapping the video card out for a 560TI,to see if that
    It can always go to a new build if necessary.

    The problem:- is the power supply man enough for the job?
    I have tried different sites for psu calculators but they vary greatly.
    One site says a 410w supply would be ok and another says it needs over
    I would like an opinion on that if possible.
    My current specs are below.
    2 80m/m case fans
    2 external sata drives (own power supply)
    speakers have own power supply

    I hope you can understand it all

    thanks again

    grylion, Nov 24, 2011
    1. Advertisements

  2. grylion

    Paul Guest

    The GTX 560TI is 160W in round numbers.


    You have a 65W processor. This would be roughly 6amps from 12V2, taking 90%
    Vcore conversion efficiency into account (YMMV). If the processor is anything
    like my E4700, it actually draws only 36W while running Prime95. But we'll
    leave this number at 6 amps for now.

    The 560TI draws 13.3 amps from 12V1. Hard drives 3*0.6amps.
    Optical drive 1*1.5 amps (boiler plate number, may be closer to 1 amp measured).
    Cooling fans estimated at 0.5 amps. Total 12V1 = 13.3+1.8+1.5+0.5=17.1 amps

    When you have a single output style power supply, you get to add 12V1
    and 12V2 consumption. That totals to 6+17.1=23.1amps worst case.

    Converting to power gives 12V*23.1A = 277.2W
    If we add another 82.5W to cover sundries, that brings the estimate
    up to around 360 watts.

    I see here, they're trying to be annoying. Ok, now I have to
    re-jig the split of the numbers. 12V1 = 2.1 +1.8+1.5+0.5= 5.9amps,
    12V2=6amps, 12V3=5.5+5.7=11.2amps, Total 12V current is still 23.1 amps.
    My assumption is 12V3 powers PCI Express pair of connectors,
    12V1 powers the slot 12V (and motherboard plus fans),
    and 12V2 powers the processor.


    3.3V @ 24A \___ 140W max Using 72.5W
    5V @ 24A /
    12V1 @ 18A \
    12V2 @ 18A >--- 480W max or 12V @ 40A Using 23.1 amps, 277.2 watts
    12V3 @ 18A /
    5V @ 3A (Allocated 10W)

    When the system starts, the hard drives draw 2.5 amps each from 12V,
    while spinning up the spindle. At that time, the video card is
    only drawing 4.4 amps instead of the maxed out 13.3, so while
    one is higher, the other is lower, and in this case, the startup
    current still isn't as high as "gaming max". But if you jam enough
    hard drives into a computer, eventually that startup current
    becomes dangerously high. Servers use staggered spin, to solve this.
    I generally don't start worrying about this, until four or more
    drives are present in the computer.

    If you replace the processor with Q9650 95W processor...

    http://support.asus.com/Cpusupport/List.aspx?SLanguage=en&m=P5K Premium/WiFi-AP&p=1&s=22

    then the power could be as high as 404W (and likely in reality,
    it's less than that). That would be operation at 78% of capacity

    In the sundry estimates, 50W is the allocation for motherboard
    and RAM. RAM power keeps dropping with each generation, and
    I don't bother to look them up any more. The 50W helps cover
    the chipset. I generally start to get nervous, if the
    power supply 3.3V or 5V rails, are rated for less than 20 amps.

    I think you're still OK with the supply you've got.

    Paul, Nov 24, 2011
    1. Advertisements

  3. grylion

    Anssi Saari Guest

    I agree. I have the same PSU powering a P5Q Deluxe, Q9550, GTX460, one
    SSD and two HDs. The 520HX is known to get somewhat loud when loaded,
    about 30 dB at 400W according to Silentpcreview's review. I haven't
    heard any noise from mine, so I assume my system is still somewhere
    below 400W. Really a shame there's no RPM output from the PSU fan.

    A GTX 560 Ti is only 20W more TDP compared to my GTX 460. I fully expect
    to be able to upgrade my video card to that without a problem. Most
    likely also to an overclocked 560 Ti also (about 190W) or GTX 570
    Anssi Saari, Nov 24, 2011
  4. grylion

    grylion Guest

    Thanks for that guys, you have been very helpful
    grylion, Nov 24, 2011
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.