Q: AsusTech : agp 8x video issues

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

Re: Asus P4P800 Deluxe -


Within 1 year I have "RMA'd" 2 brand new retail "8X" video cards, one
nvidia and one ati...both developed boot display annomylies and video
coruption in windows...

A third agp "8X" nvidia card will not run properly on this board,
locks, lags etc...but it runs flawlessly on my "P4PE" agp "4X" board.

I am running an agp "4X" card now and so far things are fine

Q: Is there any record of problems with "AGP 8X" slots on any of these
Asus products ? Possibly some bad circuit, capasitor or the slot
itself which may be specific to the "AGP 8X" feature ?

My new "RMA" replacement card is here, but I will not install it
untill I get some info or you get your board back...


ps:

-retail Antec PSU
-retail APC UPS
-tested with all periferals disconnected
-tested full load with agp "4X", OK so far...(3rd week)

Thanks for any response
6 answers Last reply
More about asustech video issues
  1. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    In article <h3cir01v3u0j2vc3t0vluj2g24vqt17it7@4ax.com>, bs@aol.com wrote:

    > Re: Asus P4P800 Deluxe -
    >
    >
    > Within 1 year I have "RMA'd" 2 brand new retail "8X" video cards, one
    > nvidia and one ati...both developed boot display annomylies and video
    > coruption in windows...
    >
    > A third agp "8X" nvidia card will not run properly on this board,
    > locks, lags etc...but it runs flawlessly on my "P4PE" agp "4X" board.
    >
    > I am running an agp "4X" card now and so far things are fine
    >
    > Q: Is there any record of problems with "AGP 8X" slots on any of these
    > Asus products ? Possibly some bad circuit, capasitor or the slot
    > itself which may be specific to the "AGP 8X" feature ?
    >
    > My new "RMA" replacement card is here, but I will not install it
    > untill I get some info or you get your board back...
    >
    >
    > ps:
    >
    > -retail Antec PSU
    > -retail APC UPS
    > -tested with all periferals disconnected
    > -tested full load with agp "4X", OK so far...(3rd week)
    >
    > Thanks for any response

    There is a power circuit on the motherboard that makes
    1.5V for the AGP 4X/8X slot. The circuit remains at 1.5V
    nominal, whether the slot runs at 4X or 8X. Both the I/O
    pads on the GPU (video card chip) and the Northbridge
    AGP pads, are powered by this supply.

    You've probably read references to AGP using 0.8V . The way
    that works, is when operating in 8X mode, the AGP lines are
    terminated with load resistors. The resistors cause the
    signal voltage to drop to 0.8V, while the I/O pads driving
    them are still actually powered by 0.8V. In a sense, this
    is still powering by 1.5V, but you'll still see references
    to 0.8V, even though the circuit is not fed by 0.8V.

    The power consumed by the I/O circuits increases, when you
    are running 8X. If the motherboard had a defect in the power
    circuit, and could not handle the load of running at the
    8X setting, that could cause flaky operation.

    You could go into "Advanced" in the BIOS, and somewhere down
    there, you'll find "AGP VDDQ Voltage". It varies from 1.5V
    to 1.8V, in 0.1V steps. If you put your AGP 8X card back
    in there, you could try adjusting the voltage, and see
    if a higher voltage makes things more stable. (Don't be
    deceived by the BIOS settings - sometimes circuits like
    this really only have a high and a low setting. They may
    not in fact have four voltages values in actual hardware.
    One Asus motherboard is like that on DIMM voltage - there
    are really only two DIMM voltages.) Try 1.8V and see if
    the 8X card you've got now becomes more stable. It shouldn't
    really need a voltage boost like this, but the improvement
    in stability could mean that when set to 1.8V, it might
    just be barely making 1.5V or something.

    There are two supply voltages that could be shared by the
    video card and the motherboard - Vagp and +3.3V. And, either
    the +3.3V could be coming direct from the power supply, or
    the +3.3V could be made on the motherboard itself. Generally,
    the other voltages, like +5V or 12V, are converted by
    switching circuits on the video card, into voltages that
    can be used by the chips, like, for example, the memory
    chips for the GPU. As such, an out of spec +5V or +12V is
    not likely to fry the video card, as the conversion circuit
    on the video card will have some tolerance to voltage error.
    But a Vagp error, like if the Vagp was producing more voltage
    on the motherboard than it was supposed to, could lead to
    the premature death of either the motherboard Northbridge or
    the video card GPU.

    Does your Northbridge run hot ? That might be a sign of
    an over-voltage problem.

    I'd recommend measuring some of the voltages on the board,
    but am embarrassed to say that I haven't been able to positively
    identify many of the power circuits on my P4C800-E (I really
    need an oscilloscope for this work, but don't own one). In any
    case, to do such measurements, you'd have to pull the motherboard
    out of the case, and sit it on the bench.

    Considering the problems you've had so far, you should consider
    either taking the motherboard to a repair place, and have them
    see if they can find Vagp and measure it. Or RMA the motherboard
    and take your chances with another one. I hope Asus will believe
    you, if you report the cause for returning the board is
    "fries video cards" :-)

    HTH,
    Paul
  2. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    On Fri, 10 Dec 2004 05:26:44 -0500, nospam@needed.com (Paul) wrote:

    >In article <h3cir01v3u0j2vc3t0vluj2g24vqt17it7@4ax.com>, bs@aol.com wrote:
    >
    >> Re: Asus P4P800 Deluxe -


    --->snip

    Wow, thanks for all the tech info paul, I can definately use much of
    that information for further annalysis.

    I have monitored the 1.5V load thru the bios and with Asus probe, both
    seem to indicate similar readings. I cannot be assurred which one is
    more accurate, however.
    But...both indicate a drop of only .12V without load and of course
    this fluctuates to minor positive incriments as well. I wish I would
    have tried the voltage adjustment in the bios when the working
    replacement card #1 was running so bad in this board... I have seen
    this setting. I probably will try it anyways...

    Now, just to add the monkey wrench, the northbridge does seem warm. In
    fact, during my trouble shooting, I could feel the warmth, not
    neccessarily heat, comming from my open chassis. This was pinpointed
    to the northbridge chip. Incidently, I ordered 2 stock P4 intel boards
    for back up measures and the northbridge heatsinks are twice the size
    of the Asus heatsink.


    But in relation to:

    >The way
    >that works, is when operating in 8X mode, the AGP lines are
    >terminated with load resistors. The resistors cause the
    >signal voltage to drop to 0.8V, while the I/O pads driving
    >them are still actually powered by 0.8V. In a sense, this
    >is still powering by 1.5V, but you'll still see references
    >to 0.8V, even though the circuit is not fed by 0.8V.

    This point may be the clue, but...

    Is this feature done on mobo or on the card ?
    If it is done on mobo, then if the load resistors are in fact not
    dropping the voltage to .8V, what would that mean ? Unless I am miss
    interpreting, this would definatly shorten the life of any AGP 8X card
    in this board running at 8X...

    I must also say that there is no AGP setting in this bios which allows
    me to set the AGP "_X" feature, so it is automatic and sets at the
    optimum...I guess.

    Thanks so much for the feedback.
    I am attempting to RMA the board and the new warranty video card is
    going in the intel board. I just like to take these hardware issues as
    far as I can, technically speaking...

    Regards,


    ñíñjà¤têç

    ---END_PGP_SIGNATURE---
  3. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    In article <0hqkr0le6dbuqgo5og3c9jp8pueb8cnj66@4ax.com>, bs@aol.com wrote:

    > On Fri, 10 Dec 2004 05:26:44 -0500, nospam@needed.com (Paul) wrote:
    >
    > >In article <h3cir01v3u0j2vc3t0vluj2g24vqt17it7@4ax.com>, bs@aol.com wrote:
    > >
    > >> Re: Asus P4P800 Deluxe -
    >
    >
    > --->snip
    >
    > Wow, thanks for all the tech info paul, I can definately use much of
    > that information for further annalysis.
    >
    > I have monitored the 1.5V load thru the bios and with Asus probe, both
    > seem to indicate similar readings. I cannot be assurred which one is
    > more accurate, however.
    > But...both indicate a drop of only .12V without load and of course
    > this fluctuates to minor positive incriments as well. I wish I would
    > have tried the voltage adjustment in the bios when the working
    > replacement card #1 was running so bad in this board... I have seen
    > this setting. I probably will try it anyways...
    >
    > Now, just to add the monkey wrench, the northbridge does seem warm. In
    > fact, during my trouble shooting, I could feel the warmth, not
    > neccessarily heat, comming from my open chassis. This was pinpointed
    > to the northbridge chip. Incidently, I ordered 2 stock P4 intel boards
    > for back up measures and the northbridge heatsinks are twice the size
    > of the Asus heatsink.
    >
    >
    > But in relation to:
    >
    > >The way
    > >that works, is when operating in 8X mode, the AGP lines are
    > >terminated with load resistors. The resistors cause the
    > >signal voltage to drop to 0.8V, while the I/O pads driving
    > >them are still actually powered by 0.8V. In a sense, this
    > >is still powering by 1.5V, but you'll still see references
    > >to 0.8V, even though the circuit is not fed by 0.8V.
    >
    > This point may be the clue, but...
    >
    > Is this feature done on mobo or on the card ?
    > If it is done on mobo, then if the load resistors are in fact not
    > dropping the voltage to .8V, what would that mean ? Unless I am miss
    > interpreting, this would definatly shorten the life of any AGP 8X card
    > in this board running at 8X...
    >
    > I must also say that there is no AGP setting in this bios which allows
    > me to set the AGP "_X" feature, so it is automatic and sets at the
    > optimum...I guess.
    >
    > Thanks so much for the feedback.
    > I am attempting to RMA the board and the new warranty video card is
    > going in the intel board. I just like to take these hardware issues as
    > far as I can, technically speaking...
    >
    > Regards,
    >
    > ñíñjà¤têç

    I didn't think AGP voltage registered on the monitor chip.
    Would that be Vcore you are looking at ?

    The terminators could be inside the GPU. I cannot really be
    sure, as the AGP standard does not address how the AGP
    I/O is actually built by companies like ATI and Nvidia.

    The termination resistors are there to make a clean looking
    trapezoidal signal. The fact that the signal swing is reduced,
    does a couple of things. It can reduce the emissions caused
    by the switching noise, and a reduced swing signal switches
    faster. The termination scheme, in fact, speeds up the signals
    two ways. The amplitude is reduced, so the signals don't have
    to go as far. And, a parallel termination type, also removes
    the RC delay associated with series damping type terminations.
    But that is a tiny number, like 250pS or so. (And with the 8X
    rate, the clocking methodology is probably such, that delay is
    immaterial anyway. I haven't read up on how the clocking works.)

    To try to detect the heat, you would need to run the motherboard
    first in 4X mode, measure the Northbridge temperature, then
    run it in 8X mode. Otherwise, it will be tough to tell the
    difference between the two standards.

    If I was looking at this, I would need to get out a
    multimeter, and find a place to monitor the AGP voltage
    on the motherboard. I would get a copy of the AGP standard
    and find out which pins on the socket have the AGP I/O voltage
    on them. Then, when the motherboard is powered up, probe the
    holes along the edge of the motherboard connector, for the pin(s)
    in question. But, you have to be very careful when doing
    stuff like that, as one slip could short the conversion circuit
    for the AGP, and burn it out. (It may not be protected, in the
    interest of saving money for Asus.) You should only try this
    with the motherboard sitting on the test bench. Clip the multimeter
    ground onto a connector lug on the I/O connectors, so the
    ground probe doesn't get in the way.

    As the AGP standard is no longer on the Intel download site,
    I use this one. Page 50 has the pinout, and the AGP voltage
    is on the pins labelled Vddq1.5

    http://web.archive.org/web/20030314013601/http://developer.intel.com/technology/agp/downloads/agp30_final_10.pdf

    Page 63 shows a picture of the signal amplitude (0.8V)
    compared to the voltage used to power the I/O pad (vddq1.5).

    On page 64, you can see a FET being used on the receiving
    chip, as a resistor to ground. That FET, is how the chip
    is able to digitally control the terminator. The terminator
    is not always enabled, and would be disabled when the card
    is set to 4X mode. In that case, the signal swings to 1.5V,
    and the power for the I/O pad is still 1.5V. (If the AGP
    I/O is bidirectional, there are probably terminators in
    both the Northbridge and the GPU - two instances of the
    circuit, pointing in different directions.)

    As far as the Northbridge temperature, other things that
    affect it, are running the DDR RAM at DDR500. Or boosting
    the DDR voltage, as the voltage used to run the memory,
    also runs the Northbridge. The Northbridge and memory
    DIMMs share common I/O signals, and generally that means
    the I/O power for the two devices will be common as well.

    Even dual channel versus single channel, makes a marked
    difference in the operating temperature.

    Looking at the AGP I/O signals themselves, would be
    pretty hard without some fancy test equipment. The AGP
    I/O runs at 533Mb/sec in 8X mode, and that means a
    5GHz digital sampling scope would be needed, for single
    shot capture. You would probably end up capturing an
    eye diagram for the I/O, rather than trying to track
    the 1's and 0's. Ah, the good ole days...

    HTH,
    Paul
  4. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    On Sat, 11 Dec 2004 06:45:31 -0500, nospam@needed.com (Paul) wrote:

    >In article <0hqkr0le6dbuqgo5og3c9jp8pueb8cnj66@4ax.com>, bs@aol.com wrote:
    >
    >> On Fri, 10 Dec 2004 05:26:44 -0500, nospam@needed.com (Paul) wrote:
    >>
    >> >In article <h3cir01v3u0j2vc3t0vluj2g24vqt17it7@4ax.com>, bs@aol.com wrote:
    >> >
    >> >> Re: Asus P4P800 Deluxe -
    >>
    >>
    >> --->snip

    snip...again...lol

    Ya, so the monitors I am reading are what is supplied to the
    slot...and I am running in dual channel mode as well.

    Even if I did get a reading off of the slot, what would be an
    exceptable votage drop? But even if there was a voltage drop, I guess
    it would explain the one card choking. Which still leaves the question
    as to why the cards are failing after an average of...4.5 months ? If
    this were the case, than the tolerance's on the GPU to reduce the
    voltage are not able to handle the possible fluctuations of the power
    supply, which maybe over the threshold allowed anyway...yes ? Hmmm...

    If time allows it, I will try to monitor the voltages as you described
    and I am going to purchase a new psu for safe measure.

    Your explanations seem very technical, which would indicate to me you
    are in a field of electronics. I certain appreciate the challenge of
    deciphering through your replies...

    Regards,


    ñíñjà¤têç

    ---END_PGP_SIGNATURE---
  5. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    In article <hq9nr09ocrbti42lmpakvh03sj3auvcdte@4ax.com>, bs@aol.com wrote:

    > On Sat, 11 Dec 2004 06:45:31 -0500, nospam@needed.com (Paul) wrote:
    >
    > >In article <0hqkr0le6dbuqgo5og3c9jp8pueb8cnj66@4ax.com>, bs@aol.com wrote:
    > >
    > >> On Fri, 10 Dec 2004 05:26:44 -0500, nospam@needed.com (Paul) wrote:
    > >>
    > >> >In article <h3cir01v3u0j2vc3t0vluj2g24vqt17it7@4ax.com>, bs@aol.com wrote:
    > >> >
    > >> >> Re: Asus P4P800 Deluxe -
    > >>
    > >>
    > >> --->snip
    >
    > snip...again...lol
    >
    > Ya, so the monitors I am reading are what is supplied to the
    > slot...and I am running in dual channel mode as well.
    >
    > Even if I did get a reading off of the slot, what would be an
    > exceptable votage drop? But even if there was a voltage drop, I guess
    > it would explain the one card choking. Which still leaves the question
    > as to why the cards are failing after an average of...4.5 months ? If
    > this were the case, than the tolerance's on the GPU to reduce the
    > voltage are not able to handle the possible fluctuations of the power
    > supply, which maybe over the threshold allowed anyway...yes ? Hmmm...
    >
    > If time allows it, I will try to monitor the voltages as you described
    > and I am going to purchase a new psu for safe measure.
    >
    > Your explanations seem very technical, which would indicate to me you
    > are in a field of electronics. I certain appreciate the challenge of
    > deciphering through your replies...
    >
    > Regards,
    >
    > ñíñjà¤têç

    There are multiple VDDQ_1.5 pins, so there really shouldn't
    be a measureable drop caused by the connector. What you see
    on the card side should be the same as the copper on the
    motherboard that carries the 1.5V power.

    Chips are intolerant to too high a voltage. Too low a voltage
    should just result in the board crashing or applications
    erroring out (like a 3D game quitting unexpectedly). With
    too high a voltage, the circuit will still function properly,
    but it will be under a life shortening stress.

    I still think you aren't going to know for sure what is going
    on, without measuring at the socket, as at least there, you've
    got a pinout in the AGP30 spec to work with. A supply problem
    is certainly the easiest to visualize as the source of the
    trouble, but even one messed up signal on the interface could
    do it. That is why, at some point, an RMA might be the only
    way to solve the dilemma, and give you some peace of mind.

    HTH,
    Paul
  6. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    On Tue, 14 Dec 2004 01:31:04 -0500, nospam@needed.com (Paul) wrote:

    >In article <hq9nr09ocrbti42lmpakvh03sj3auvcdte@4ax.com>, bs@aol.com wrote:
    >
    >> On Sat, 11 Dec 2004 06:45:31 -0500, nospam@needed.com (Paul) wrote:
    >>
    >> >In article <0hqkr0le6dbuqgo5og3c9jp8pueb8cnj66@4ax.com>, bs@aol.com wrote:
    >> >
    >> >> On Fri, 10 Dec 2004 05:26:44 -0500, nospam@needed.com (Paul) wrote:
    >> >>
    >> >> >In article <h3cir01v3u0j2vc3t0vluj2g24vqt17it7@4ax.com>, bs@aol.com wrote:
    >> >> >
    >> >> >> Re: Asus P4P800 Deluxe -
    >> >>
    >> >>
    >> >> --->snip
    >>
    >> snip...again...lol
    >>
    >> last snip...?

    Thanks Paul, been away for a while, but I am back with my replacement
    card and a new mobo.

    It looks like I'll have to keep the "possibly bad" mobo, so I will be
    able to setup some kind of test bench. Not sure aht to do with the
    results, but it sure is fun...heh

    Regards,
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