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  1. #1
    Joined
    Nov 2004
    Location
    Boulder CO
    Posts
    4

    HELP CPU Voltage fluctuations

    what is typical for voltage fluctuations for AMD Athlon 64 chips? Mine seem high.

    At stock voltage settings I'm getting fluctuations from 1.33V all the way to 1.44V according to CPU-Z v1.25.2 AND MSI CoreCell. I'm running through a belkin UPS on a dedicated 30 amp line in my house, so voltage fluctuations there shouldn't be a problem.

    It's a brand new system I just put together. Thermaltake Silent pure power 420W supply, AMD Athlon 64 3000+ winchester, 2 Hitachi SATA 80 Gig drives, Zalman 7000B CU HS.

    So, should I be worried about an almost 10% fluctuation in CPU voltage or not???

    Doc

  2. #2
    Joined
    Apr 2003
    Location
    Connecticut
    Posts
    265

    Re: HELP CPU Voltage fluctuations

    Quote Originally Posted by Dr.Groveller
    what is typical for voltage fluctuations for AMD Athlon 64 chips? Mine seem high.

    At stock voltage settings I'm getting fluctuations from 1.33V all the way to 1.44V according to CPU-Z v1.25.2 AND MSI CoreCell. I'm running through a belkin UPS on a dedicated 30 amp line in my house, so voltage fluctuations there shouldn't be a problem.

    It's a brand new system I just put together. Thermaltake Silent pure power 420W supply, AMD Athlon 64 3000+ winchester, 2 Hitachi SATA 80 Gig drives, Zalman 7000B CU HS.

    So, should I be worried about an almost 10% fluctuation in CPU voltage or not???

    Doc
    Well either ur PS is making it fluctuat OR in my paranoid mind if u hooked up ALOT of stuff to the same one or two power connectors. Example. 3 hds, 1 dvdrw, video card, all fans to one or two power plugs! I think if u do that because ur putting the load on one set of wiring u may get this exact symptom but not sure. Did u do that when u assembled ur setup? I have alot of stuff in my rig and i get about 5% fluctuations even though i have a real strong PS. But 10% is defintly something weird especially since i have alot more stuff in my rig and i'm OCed!
    DFI NF4 SLI-DR w/ 3700+ Sandy @ 2500+ mhz
    2x1gb g.skill Ram @ 250 mhz @ 2.5-3-2-0-1T
    XP-120 w/ YS-Tech 120 mm Fan
    X-Superalien Blue Aluminum Case
    BFG 7800GTX @ stock speeds!
    NEC 3500A 16X DVD-RW Drive
    Silverstone Zeus 650w PowerSupply!

  3. #3
    Joined
    Sep 2003
    Location
    Canada
    Posts
    172

    Re: HELP CPU Voltage fluctuations

    what motherboard do you have? i'm not sure its all that acurate. my neo2 fluctuates a lot. i think the bios is buggy reading that info still... i'm not too concerned about it.

    i have an OCZ powerstream PSU 470w, and on the back there are LEDs that show how much power the 12, 5 and 3 volt rails are actually giving. and i can actually tweak it to compensate for whatever. but i have them tweaked to give almost exactly the right values but CPU-z still reports wacky vcore on my winny/neo2 combo.
    Shuttle: SN95G5 v1.3 - BIOS: "Q"
    CPU: AMD64 3200+ 90nm Wk37 @ 2.475 GHz (275x9 @ 1.5v)
    RAM: 2x 512MB PQI Turbo PC3700 @ 225 MHz 2.5-4-4-8 (1T) @ 2.6v
    HD: 2x Seagate 7200.7 80GB SATA
    Video: XFX GeForce 6600 GT (noisy monster)
    Optical: Pioneer DVR-108
    Display: 2x Samsung 173T DVI

  4. #4
    Joined
    Oct 2004
    Posts
    991

    Re: HELP CPU Voltage fluctuations

    This was answered by another person in the duplicate thread you posted...

    If in fact the voltages measured at the Mobo with an accurate digital volt meter show the figures you are getting from software, then you'd just be within the 5% ATX specs for voltage. This should not cause problems unless it drops below 1.33V.

    See section 3.2.1 of this ATX PSU specification guide:

    http://www.formfactors.org/developer...20Ratified.pdf

  5. #5
    Joined
    Apr 2003
    Location
    Connecticut
    Posts
    265

    Re: HELP CPU Voltage fluctuations

    Quote Originally Posted by spacey
    what motherboard do you have? i'm not sure its all that acurate. my neo2 fluctuates a lot. i think the bios is buggy reading that info still... i'm not too concerned about it.

    i have an OCZ powerstream PSU 470w, and on the back there are LEDs that show how much power the 12, 5 and 3 volt rails are actually giving. and i can actually tweak it to compensate for whatever. but i have them tweaked to give almost exactly the right values but CPU-z still reports wacky vcore on my winny/neo2 combo.

    But isn't voltage at the PS and the mobo different? Power drop, wiring, etc. all affect voltage differences between the PS and the mobo itself. But yes some mobos do report wrong as mine goes up even alittle on the 12v line (11.9-12.1) and even OCed it NEVER crashes so yeah somebody is lieing!
    DFI NF4 SLI-DR w/ 3700+ Sandy @ 2500+ mhz
    2x1gb g.skill Ram @ 250 mhz @ 2.5-3-2-0-1T
    XP-120 w/ YS-Tech 120 mm Fan
    X-Superalien Blue Aluminum Case
    BFG 7800GTX @ stock speeds!
    NEC 3500A 16X DVD-RW Drive
    Silverstone Zeus 650w PowerSupply!

  6. #6
    Joined
    Oct 2004
    Posts
    991

    Re: HELP CPU Voltage fluctuations

    If there is enough resistance in the wiring from the PSU to the Mobo to show a voltage drop then you need a different PSU as most use 16 AWG. wire, per the ATX PSU specs. The ATX specs are +/- 5% on voltages, so in theory you could have an extreme voltage swing of 10% total.

    That being said... Any PSU that doesn't hold STEADY rail voltages is not worth JACK in a PC. Stable voltages, not just voltages within +/- 5%, are critically important in a PC for system performance and stability. If the voltages are moving around your PSU is poor quality and it will cause you problems.

  7. #7
    Joined
    Jan 2004
    Posts
    3,463

    Re: HELP CPU Voltage fluctuations

    PSU rarely casues CPU voltage fluctuation. It's usually the motherboard.

    A bit of fluctuation is not at al abnormal. The amount your getting is higher than I have personally seen, but unless it's casuing stability problems, I wouldn't worry about it.

  8. #8
    Joined
    Sep 2003
    Location
    Canada
    Posts
    172

    Re: HELP CPU Voltage fluctuations

    ya mine vary from like 1.516 to 1.566v

    shrug, the ocz powerstream 470w is suppose to be a quality psu so i'm taking that for granted.
    Shuttle: SN95G5 v1.3 - BIOS: "Q"
    CPU: AMD64 3200+ 90nm Wk37 @ 2.475 GHz (275x9 @ 1.5v)
    RAM: 2x 512MB PQI Turbo PC3700 @ 225 MHz 2.5-4-4-8 (1T) @ 2.6v
    HD: 2x Seagate 7200.7 80GB SATA
    Video: XFX GeForce 6600 GT (noisy monster)
    Optical: Pioneer DVR-108
    Display: 2x Samsung 173T DVI

  9. #9
    Joined
    Apr 2003
    Location
    Connecticut
    Posts
    265

    Re: HELP CPU Voltage fluctuations

    Quote Originally Posted by spacey
    ya mine vary from like 1.516 to 1.566v

    shrug, the ocz powerstream 470w is suppose to be a quality psu so i'm taking that for granted.
    I have a vantec 470a PS that could probably power a nuclear sub! Yet i still get small fluctuations! I blame the mobo or the sensors! =x Not to mention that the temp readings are atleast 10C to low as my current case temp after mobo/cpu/heatsink change over dropped about 10C and my cpu temps seem to be off about the same as well as they are about where my case temp used to be!
    DFI NF4 SLI-DR w/ 3700+ Sandy @ 2500+ mhz
    2x1gb g.skill Ram @ 250 mhz @ 2.5-3-2-0-1T
    XP-120 w/ YS-Tech 120 mm Fan
    X-Superalien Blue Aluminum Case
    BFG 7800GTX @ stock speeds!
    NEC 3500A 16X DVD-RW Drive
    Silverstone Zeus 650w PowerSupply!

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