Do I need a new PSU?

Discussion in 'Tech Chat' started by lonesome killer, Nov 2, 2013.

  1. lonesome killer

    lonesome killer Banhammered

    Here's my current setup.
    ASUS Crosshair IV Formula AM3 AMD 890FX SATA 6Gb/s USB 3.0 ATX AMD Motherboard
    http://www.newegg.com/Product/Product.aspx?Item=N82E16813131644

    2 x GIGABYTE GV-R695OC-1GD Radeon HD 6950 1GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card
    http://www.newegg.com/Product/Product.aspx?Item=N82E16814125385

    OCZ ModXStream Pro 700W Modular High Performance Power Supply
    http://www.newegg.com/Product/Product.aspx?Item=N82E16817341018

    AMD Phenom II X4 970 Black Edition Deneb 3.5GHz Socket AM3 125W Quad-Core Desktop Processor HDZ970FBGMBOX
    http://www.newegg.com/Product/Product.aspx?Item=N82E16819103894

    I'm replacing the graphics card with this:
    Sapphire Radeon R9 280X 3GB
    http://www.newegg.com/Product/Product.aspx?Item=N82E16814202045

    It says it needs 750 Watt and I have a 700 now. I don't know about power requirements :(
     
  2. VintagePC

    VintagePC GodModePC (One-man Show) VF4-S (Server Operator) Forum Operator Minecraft Operator Global Moderator Staff Member DMC Tester Jailbreak Admin TF2L developer

    It's kinda hard to say at this point. PSU wattage is rather a poor estimate of power draw/capacity, and assuming the 750 comes from the new card's requirements, it is calculated based on having a certain percent of your system loaded down already, which may not be true for you - and that is also probably a peak draw value, which means everything in your system would draw the maximum.

    What you would "really" need to look at is the per-rail current draw - i.e. how many amps your current supply is capable of providing on the +3.3, +5 and +12V lines, along with how much the new card draws, to see if your supply can do it. That's really frigging tedious and barely anyone does it though :/ but the point is that it differs from supply to supply - for example, two 750W supplies, one might be able to offer 20A on the 5V rail, and 30A on the 12V rail, for 460W on those two rails... Or, you could be getting 25A on the 12V rail, and 32A on the 5V rail - still 460W but the distribution is different.

    That said, you have a decent quality/brand of power supply... with the numbers that close, it could well be okay for ONE of those cards. I wouldn't recommend even considering it with cheap garbage no-brand PSUs though. Those rarely even make their stated peak power.
    You'll definitely need a new supply if you want to crossfire those (1000+ watts)
    At the very least, see if you can find info on the PCIE capacity of your PSU and verify that you can meet the one 150W 8-pin and one 75W 6-pin requirement listed.
     
  3. lonesome killer

    lonesome killer Banhammered

    Speak English VintagePC! The card's coming in a couple days so I think the easiest way is to just try it.

    I'm not planning on cross firing it.
     
  4. VintagePC

    VintagePC GodModePC (One-man Show) VF4-S (Server Operator) Forum Operator Minecraft Operator Global Moderator Staff Member DMC Tester Jailbreak Admin TF2L developer

    'scuse me for thinking you were interested in learning what to look at :p

    Just keep in mind that if you see any weird stuff like artifacts, random resets, or other problems, that it could well be a lack of power rather than a defective card. Insufficient power can produce some weird symptoms.
     
  5. Reechard

    Reechard Server Admin VF4-S (Server Operator) Minecraft Operator Staff Member Minecraft Admin

    yeah most circuits will allow for a 10% drift.... Not so much with GPUs.
     
  6. lonesome killer

    lonesome killer Banhammered

    Well what do you recommend?
     
  7. VintagePC

    VintagePC GodModePC (One-man Show) VF4-S (Server Operator) Forum Operator Minecraft Operator Global Moderator Staff Member DMC Tester Jailbreak Admin TF2L developer

    Try it, and if you have problems the first thing you should suspect is that you need a new power supply.
     
  8. lonesome killer

    lonesome killer Banhammered

    I mean if it is the PSU what PSU would you recommend?
     
  9. VintagePC

    VintagePC GodModePC (One-man Show) VF4-S (Server Operator) Forum Operator Minecraft Operator Global Moderator Staff Member DMC Tester Jailbreak Admin TF2L developer

    OK, my bad.

    My only real advice for a PSU is "don't cheap out". Cheap ones are garbage; go with a known brand like Corsair, OCZ, and Antec. There may be a few others but those are the major players that know how to make good stuff, so go with one of them.

    Other than that, find one with the wattage you need, modular cables if you want it, and you should be good.

    This one is currently on sale:
    http://www.newegg.com/Product/Product.aspx?Item=N82E16817139051

    It's 750W, but if you are even remotely thinking of crossfiring another one of those cards I'd consider going higher for sure.
     
  10. Reechard

    Reechard Server Admin VF4-S (Server Operator) Minecraft Operator Staff Member Minecraft Admin

    You have an OCZ PSU and I'm pretty sure you said you were running SSD.... as long as you don't have like, 4 hard drives and 12 fans in your case you should be OK. I've used CoolerMaster PSUs for my last 3-4 builds and I can't fault them at all, they're pretty great.
     
  11. VintagePC

    VintagePC GodModePC (One-man Show) VF4-S (Server Operator) Forum Operator Minecraft Operator Global Moderator Staff Member DMC Tester Jailbreak Admin TF2L developer

    Only thing I remember was some of their 1000W ones being flaky... maybe that's gotten better now.
     
  12. lonesome killer

    lonesome killer Banhammered

    Ok I got everything installed and it's working great. Thanks guys!
     
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