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Thread: Computer running slower after BIOS update




  1. #11
    synack's Avatar
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    Default Re: Computer running slower after BIOS update

    8Bitlove2a03,
    Do me a fav? Can you pop into your BIOS and tell me what your vcore is set to? I've dug around and found a couple places where the default vcore was 1.3v + which IS WAAAAY to high for stock frequencies.
    Stock voltage should be around 1.15v for the 95w CPU.
    I'm not sure which flavour of the 8120 you have. (one is 95w TDP, the other is 120w. 95 should be the model you have for that motherboard)
    But assuming you have the 95w, lets plug in a few calculations...

    Current = Power/Volts
    I = 95/1.15 = 82.6 amps

    now to calculate the dif in power with an increase in volts, we need to calculate the CPU's resistance. (load)
    Resistance = Volts/Current
    R = 1.15/82.6 = .0139225 Ohms

    Now lets go backwards with say 1.3v vcore

    Current = Volts/Resistance
    I = 1.3 / .0139225 = 93.4 Amps

    Power = Volts * current
    P = 1.3 * 93.4 = 121Watts

    Hold up... Interesting that I get 120 watts... I wonder if a CPU update changed the vcore from 1.15 to 1.3v to support the 120W processor?!?
    Now I really want to know what your vcore is!!

    Anyway, my point was that a change from 1.15v to 1.3v changes the watts from 95 to 120! Thats 25 more watts for the fan to cool. that's a bit more than a 25% increase in heat from about 13% increase in voltage.

    (any electronics engineers out there: yes, I didn't take some things into account like temperature, inductance/frequencies. My intention was a simplistic view of the power consumption and dissipation, so don't flame me ok? haha. It's close enough in this context )

    Syn

  2. #12
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    Default Re: Computer running slower after BIOS update

    I'd like to see a CPU-Z screenshot of your CPU, which you can download here, free, and I guarantee it is safe:

    CPUID - System & hardware benchmark, monitoring, reporting

    All I'd like to see is the main, CPU tab screen. It will show you other (mind boggling) info about your PC.

  3. #13
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    Default Re: Computer running slower after BIOS update

    Quote Originally Posted by synack View Post
    8Bitlove2a03,
    Do me a fav? Can you pop into your BIOS and tell me what your vcore is set to? I've dug around and found a couple places where the default vcore was 1.3v + which IS WAAAAY to high for stock frequencies.
    Stock voltage should be around 1.15v for the 95w CPU.
    Vcore is about 1.32v, and it's the ~124w version.

    Quote Originally Posted by parsec View Post
    I'd like to see a CPU-Z screenshot of your CPU, which you can download here, free, and I guarantee it is safe:

    CPUID - System & hardware benchmark, monitoring, reporting

    All I'd like to see is the main, CPU tab screen. It will show you other (mind boggling) info about your PC.
    Here's that screenshot http://i.imgur.com/7mqMA.png

  4. #14
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    Default Re: Computer running slower after BIOS update

    Ok, you answered my (hidden) question in your answer to Syn, and with the CPU-Z screenshot. I wanted to know the Max TDP (Thermal Design Power) of your CPU, which is 124W, or the rated 125W by AMD. It's weird to me that CPU-Z shows 124, since that should be a value it reads from the CPU from data set at the factory. Sometimes these programs make mistakes or are not updated for new CPUs, but yours should be compatible now.

    The reason why I am fussing over the TDP of your CPU, is this (from the N68-VS3 FX manual):

    This motherboard supports CPU up to 95W. Please refer to our website for
    CPU support list. ASRock website HTPC, Home Theatre PC Manufacturer & Supplier - ASRock Inc.

    That is Caution 2. in the manual, section 1.2 Specifications. A similar spec can be found on your boards page on ASRock web site, in Product Specifications:

    - Support up to 95W Socket AM3+ processors
    - Support up to 95W Socket AM3 processors: AMD Phenom™ II X6 / X4 / X3 / X2 (except 920 / 940) / Athlon II X4 / X3 / X2 / Sempron processors
    - Supports 8-Core CPU


    Simply going by this information, which is general, it looks like the CPU is beyond the rated capacity of the board. We don't know if ASRock has a revision of this board made for IBuyPower, which is possible. All of the N68 boards ASRock lists currently are rated for 95W CPUs.

    AMD lists four versions of the FX-8120 CPU, three rated at 125W, one with "unavailable", but everything I have seen so far indicates your CPU is a 125W version.

    I don't want you to get worried about this, or become upset, since there is missing information, and if this is correct, it is not a big disaster.

    Intel uses TDP as the amount of heat a CPU cooler must be able to dissipate to keep the CPU from overheating. AMD's use of TDP is different, given what I know, but I am not an AMD expert, I'm an Intel user. I hope some AMD users can add some insight into this. There may also be settings in the BIOS, not available to the user, that allow a 125W CPU to be used in a 95W board.

    My main and really only point is that this apparent mismatch of the CPU and board is likely a factor in the high CPU temperatures you are getting. BTW, I would NOT disable thermal throttling, that is a protection feature for the CPU, with that off and if no other protections exist on the CPU, it could be damaged permanently!

  5. #15
    synack's Avatar
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    Default Re: Computer running slower after BIOS update

    Hmm.. 124w? I bet CPU-Z is calculating the TDP instead of reading it. (TDP=C*v^2*f according to wikipedia, which comes out to about the same as my calculations)
    since voltage is in the calculation, the TDP will be skewed based on current voltage setting.

    The problem with the above TDP formula is the "C" part, which is total system(processor) capacitance. We sort of need to rely on the manufacturer to supply the correct value. Since this value is the "average" heat in wattage which needs to be dissipated, based on some arbitrary guideline for "normal" usage, it leaves a LOT of room for manufacturers to fudge the TDP of any given processor.
    it's not uncommon for a 125w TDP processor to hit 200w on full load for instance. So I would take any TDP spec with a grain of salt.

    however, using TDP as a general guideline is good thing to do. I am disturbed somewhat if the processor is actually 125w on a 95w board. Heat dissipation aside, that's a 30% increase in power requirements from the board.

    Are you able to drop the vcore at all? i'm hoping you can make it down to 1.15v. If you can, just to satisfy my curiosity, let us know what cpu-z reports as the TDP after you drop the voltage. 124 is not a normal setting number, so I'm pretty sure its a calculation.

    Note: you have a nice little "clear cmos" button on the back, that will reset all of your settings to factory default if your system becomes unusable after messing with the BIOS.

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    Default Re: Computer running slower after BIOS update

    Quote Originally Posted by synack View Post
    Hmm.. 124w? I bet CPU-Z is calculating the TDP instead of reading it. (TDP=C*v^2*f according to wikipedia, which comes out to about the same as my calculations)
    since voltage is in the calculation, the TDP will be skewed based on current voltage setting.

    The problem with the above TDP formula is the "C" part, which is total system(processor) capacitance. We sort of need to rely on the manufacturer to supply the correct value. Since this value is the "average" heat in wattage which needs to be dissipated, based on some arbitrary guideline for "normal" usage, it leaves a LOT of room for manufacturers to fudge the TDP of any given processor.
    it's not uncommon for a 125w TDP processor to hit 200w on full load for instance. So I would take any TDP spec with a grain of salt.

    however, using TDP as a general guideline is good thing to do. I am disturbed somewhat if the processor is actually 125w on a 95w board. Heat dissipation aside, that's a 30% increase in power requirements from the board.

    Are you able to drop the vcore at all? i'm hoping you can make it down to 1.15v. If you can, just to satisfy my curiosity, let us know what cpu-z reports as the TDP after you drop the voltage. 124 is not a normal setting number, so I'm pretty sure its a calculation.

    Note: you have a nice little "clear cmos" button on the back, that will reset all of your settings to factory default if your system becomes unusable after messing with the BIOS.
    I dropped the voltage by .1 volts (from 1.3250v to 1.2250v). According to CPU-Z the TDP remains 124W (another CPU-Z screenshot).

    I am so far out of my depth at this moment that it has stopped being funny.

  7. #17
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    Default Re: Computer running slower after BIOS update

    huh... I could have sworn it would have dropped down.
    Either way, running at a lower voltage WILL run the CPU cooler than before.
    Maybe -.1 is enough to keep you going.

    Give it a spin and see how it goes. You can always try and drop it another .05 if you want as well.

    Hang in there. You are learning more than you probably will ever need to know. But I like to give explanations along the way, so you and others understand the reasoning.

    Syn

  8. #18
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    Default Re: Computer running slower after BIOS update

    "I am so far out of my depth at this moment that it has stopped being funny."

    We understand, but in tracking down the situation with that PC, all this other information came up. Yes it's fairly deep into PC nerd land, but that's what happens when you cross the road from ignoring the mysterious black box, to wanting to know why it is not doing what it should be doing. No offense, just FYI, this stuff is just scratching the surface... Most people do not know any of this stuff. We've been doing it for years, it's a hobby. Some people build model aircraft, we build PCs. We use them too, so it's not a total waste of time and money, or I should say, it's not just for fun.

    Our fault too, we dived right into full techo speak, hard for us not to. We need to back off and be more general. Let me think about it.

    But you know somewhat what is going on, so where are you at now, let's try kinda starting over again.

  9. #19
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    Default Re: Computer running slower after BIOS update

    Alright, so playing with the voltage turned down by .1v, the CPU is around 5C cooler while playing games. There was also a bit of a performance increase, though it's still not what it was. Once I get the chance to mess with it some more I'll see about stepping down the voltage a bit more. Hopefully that improves it some more, though I'm still going to have to talk to iBuypower about the original settings.

    On that note, obviously I'm going to have to ask about this apparant TDP miss-match, but I don't know where to begin. From what I'm gathering from you guys and a lot of Googling, my understanding is that a 125W CPU draws more power and generates more heat than the 95W mobo is designed to handle. If that's the case, then should I be telling iBuypower they used the wrong version of the CPU and they need to fix it before damage is done to the board? Or is this something that isn't uncommon and can be dealt with some other way?

  10. #20
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    Default Re: Computer running slower after BIOS update

    It could very well be that they were using 125W processors, but running them undervoltage to 95w. essentially it's the same thing anyway. The difference being one is "rated" for a particular voltage/wattage, while another is not.

    It's actually common place for hardware nerds like us, to reduce the voltage as much as possible for the chosen frequency. While keeping the system still stable of course.
    for example, the computer I'm on right now, when I'm not overclock benching, I run my 3770k CPU slightly overclocked at 4Ghz but run the voltage at about 1v. Running highly efficient water cooling my idle temps are like 2-3c over ambient air temperature. fully loaded my CPU never goes above 52c.

    you might benefit from prime95 or some program like that. prime95 can REALLY max out processors. set it to "small ffts" and it'll really make your CPU hum. it's more accurate for testing CPU heat and loads than playing a game. But in the end, how something feels to you is important. Just saying that prime95 will be a little more quantitative.

    It's really good to hear you are making progress though.

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