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What's the PCIe power specs allowed for each 1.0 , 1.1a , 2.0 , 2.1 and 3.0 rated slot?

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2011/09/24 16:01:04 (permalink)
Hi, I'm trying to confirm something about the specs, regarding the PCIe power allowed, on each of the different versions of the PCIe standards.

I thought the PCIe 1.0 and 1.1a x16 slots only allowed 60 watts for v1.0 and 75 watts on v1.1a, and that only 2.0 and higher allowed higher wattage from the motherboards PCIe slot.

Some searches, on Google, said I'll need 18 amps on the 12 volt rail and at least a 300 watt power supply to run the card properly. (e-GeForce 7600 GT shown in the B-stock section)

What if the computer being used runs off of a 12 volt supply (16 amps) nearly 200 watts (192w), does the 7600 GT really take 18 amps in this case, or just the limit of the PCIe 1.1a standard my motherboard is?

I'm estimating the needed power to just be around 6 amps, (75 watts at 12 volts), am I correct, or am I in trouble?

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    lehpron
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    Re:What's the PCIe power specs allowed for each 1.0 , 1.1a , 2.0 , 2.1 and 3.0 rated slot? 2011/09/24 16:27:29 (permalink)
    The PCI-SIG organization is behind the spec, they would have more detail info than I am summarizing...
     
    PCIe 1.0/1.1/2.0 all have the limitation of 75W (6.5A at 12v) in the slot.  The difference is in the 8-pin external connector, 1.0/1.1 is 100W while 2.0 draws 150W.  The 6-pin is still 75W for either standard.  A 7600GT has no external connections, so it will never draw more than the 75W it can from the slot.  The power and bandwidth is limited by the slot specs.  For example, a PCIe 2.0 card will function 1.1 in 1.1 slot, while a 1.1 card won't perform any better in a 2.0 slot than compared to a 1.1 slot.
     
    This older review shows the typical power consumption or 7600GT at the frequencies shown is 67W.
     
    Typically, the box recomendations are specifically known as "Total System" which means the video card plus some random/basic components.  The problem is we don't know what componenets because nVidia doesn't tell us.  The deal is not everyone knows what their system uses, they don't own a powermeter to tell how much space is left.  Unless you tell us you system specs, we can't even guess.
     
    Or you can do away with the math hassle and guesses by getting better PSU.
     
    NOTE: The recommendation is part warranty and part liability.  Should something ever go wrong with the card, one of the first questions tech support will ask is your PSU wattage.  If you don't meet their minimum, they will either scapegoat the PSU as the problem, or worse, void your warranty citing you didn't follow the rules.
     
    You have to be confident of your current system's usage, the batch quality of your graphics card and PSU to not follow the rules.
    post edited by lehpron - 2011/09/24 16:29:46

    For Intel processors, 0.122 x TDP = Continuous Amps at 12v [source].  

    Introduction to Thermoelectric Cooling
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    Re:What's the PCIe power specs allowed for each 1.0 , 1.1a , 2.0 , 2.1 and 3.0 rated slot? 2011/09/24 17:11:42 (permalink)
    Thanks, your statement of 6.5 amps (75watts) on the slot is what the EVGA support tech and myself were figuring as well.

    Being no other separate power connectors were needed on the card, I'll be good to go with my 16 amp 12 volt supply brick.

    I figured out I can mod a HP ThinClient model T5730 to accept an AMD Turion x2 Dual-Core 2.4 GHz CPU. (TMDTL68HAX5DM) I already tried the 2.2GHz one, and it worked, and found out, looking at the motherboards chips data sheets, it also supports, and already has, a PCIe x16 v1.1a slot on-board now.

    I was able to put a 2.5 Inch hard drive in, and install Windows 7 , and it all worked, but saw the graphics chip on the motherboard was holding the rating back.

    The EVGA tech suggested the 7600 GT card... And they'll still honor the 90 day warranty.

    Adding up all the wattage being used before the 7600GT Is installed, I'll still have some "head-room" to spare, even with the graphics card in.

    I had to also purchase a PCIe x16 flex-card extender, as well as the female-to-female 44-pin IDE cable, and the new 16 amp 12 volt power-brick... And now can't wait until Monday, Tuesday, and Wednesday, when all the other items come in, to test all this out.

    *** Edit- forgot to also say, a Fan was added to keep the baby cool with the Dual-Core in.

    The system is mostly being used for HDTV 1920x1080 out to a HDTV for video recording of TV shows and playing Blu-Ray movies.

    (Digital Video Recorder / Server for private use.)


    May I also say, ... This site is amazing.

    Within minutes of posting my question, ... I received an answer!

    Thanks!
    post edited by NewestUser - 2011/09/24 17:20:59
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