A8V - Rev 2 vs Rev 1

Discussion in 'Asus' started by CapeGuy, Mar 4, 2005.

  1. CapeGuy

    CapeGuy Guest

    When I bought my A8V from NewEgg in mid-January, I received
    a Rev 1 board. Subsequently, I heard that Rev 2 boards had been
    shipping since November or so. Am I missing anything significant
    by having the older Rev 1 board? Also, is it typical for NewEgg to
    ship "out of date" stuff without letting the customer know?
    CapeGuy, Mar 4, 2005
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  2. CapeGuy

    Paul Guest

    AGP/PCI lock is officially supported on Rev.2

    Paul, Mar 4, 2005
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  3. CapeGuy

    RonK Guest

    Hey Paul, What is AGP/PCI lock and what does it do ?
    RonK, Mar 4, 2005
  4. CapeGuy

    sean Guest

    I would send it back and get the latest release of the board. It is fair
    to expect that when you buy a new motherboard, it should be the latest
    release, especially when it has been out for a few months. NewEgg are
    trying to flogg their old stock to you.

    sean, Mar 4, 2005
  5. CapeGuy

    Paul Guest

    An AGP/PCI lock keeps the clocks at 66.66/33.33 MHz, while
    you are overclocking. On previous generations of boards lacking
    this feature, as you raised the FSB frequency, the AGP and
    PCI would go up also. Once PCI, which is normally 33MHz, goes
    above about 37.5MHz, you could corrupt an IDE disk drive, as
    they did the timing on the drive interface with the PCI clock.
    (Not all boards did that, just the stupid ones :) And if it
    wasn't the IDE interface, then at perhaps 40MHz, the rest of
    the PCI bus would break.)

    To make a working AGP/PCI lock requires a couple of things.
    It needs the chipset to be designed with asynchronous clocking.
    That means normally one clock signal would enter a certain
    part of the chip, and for a lock, you need a separate clock for
    two parts of the circuit. Special precautions must be made
    to pass data between the two domains. (I suspect these requirements
    weren't met properly on the chipset of the A8V rev one, and
    Asus had to disable the lock on the rev one, to avoid problems
    with the chipset. It was fixed on rev two. If you are not an
    overclocker, the lock is a "don't care" feature you will never

    The second requirement, is a flexible clockgen chip, that can
    hold the AGP/PCI clock at a constant frequency, while changing
    the FSB.

    Even with all this fancy mumbo-jumbo, the new boards do have
    problems with the SATA interface. It seems mobo designers
    learn the same lessons over and over again, as there are some
    SATA interfaces on motherboards that malfunction when you
    overclock past a certain point. That is why it pays to read
    the reviews for your motherboard on Anandtech, as they sometimes
    mention which interfaces can suffer from corruption.
    Seasoned overclockers pick their disk drive interface with
    great care, due to the potential to lose the contents of the
    disk drive while experimenting.

    Paul, Mar 4, 2005
  6. CapeGuy

    RonK Guest

    Thanks a lot for the info Paul.
    My A8V is revision 1 but I have had no problems running it at 10% overclock.
    RonK, Mar 4, 2005
  7. CapeGuy

    Highlandish Guest

    I'm about to manually OC my rev 1 with a 939 3000+ to a 3800+. is this going
    to effect my ide/sata bus?
    Highlandish, Mar 4, 2005
  8. CapeGuy

    Paul Guest

    That is going from 1800MHz to 2400MHz. A 33% overclock.

    I'd take a look through this thread. Early in the thread,
    some people are using a modded BIOS, and it shows an item
    for the lock. They seem to be able to run high clocks on
    the FSB (but they are also careful as to how they connect
    a hard disk). This thread is too long for me to read the
    whole thing.


    I think you really need to find an overclocking summary
    thread. This link was posted in this group a few days


    The K8V is a board that doesn't have a working lock, and
    it hits a "wall" at 237MHz. If the A8V Rev1 is going to go
    farther than that, maybe the modded BIOS will help. So far
    I haven't read a thread, where someone tries to overclock
    a Rev.1 in its "out of the box" state. Sounds like plenty
    of experiments to come...

    Paul, Mar 5, 2005
  9. CapeGuy

    CapeGuy Guest

    If I'm not interested in overclocking, is there any
    other reason that Rev 2 may be better than Rev 1?
    CapeGuy, Mar 5, 2005
  10. CapeGuy

    Highlandish Guest

    thanks, I read the latter mentioned link to oc the a8v, but the first link
    was great, lots of info there too. little question, I currently have the
    1009 bios, is that pci locked? will it hurt to go back to the modded 1005.21
    Highlandish, Mar 5, 2005
  11. CapeGuy

    Wayne Fulton Guest

    I bought an A8V from NewEgg in early December, with 1008 BIOS.
    It says Rev 2.0 printed on the motherboard.

    However CPUZ and Asus Probe say Rev 1.xx.
    Sounds like something in BIOS is not updated ?
    Wayne Fulton, Mar 5, 2005
  12. CapeGuy

    Paul Guest

    If you look at the cpusupport web page, 1005 isn't even on the
    radar, so I don't know what will happen if you flash back to
    that old a BIOS. If you had an even older BIOS than that, to
    start with, and were able to boot, it is probably safe to use
    1005. But there are likely stability improvements in the later
    BIOS, so it is a tough call.

    In terms of what entry to expect in the BIOS screen, I wasn't
    able to find a picture of an A8V screen with the lock setting.
    If you look at the A8V-E PDF user manual, in Advanced:Frequency
    Configuration, it has:

    PCI clock sync to CPU [Enabled]
    PCI clock 33.0MHz

    The [Enabled] setting means "not locked". Basically what
    happens, is the unchangable value below the control, is
    a simple divide from the FSB, like 198/6=33.0 . As you increase
    the clock from 200 to 227, the PCI clock will rise to 37.8MHz.

    If you set that setting to [Disabled], then you are locked. The
    PCI clock setting below should become [33.0MHz] , where the
    bracket is indicating that you can change the value. Generally
    only a few options would be available, like [Auto,33.0,37.5MHz].
    A setting of 33.0 is the best choice (not auto, because sometimes
    BIOS do stupid things on auto).

    I'm hoping the A8V-E BIOS is based on the A8V BIOS, when I suggest
    that is what the interface looks like. Asus never updates the manual
    if the BIOS feature set changes, so I cannot expect to ever see
    a manual page for how this would look on the A8V.

    If, in the 1009 BIOS, you have the above two entries or something
    similar, then you likely don't need 1005.

    When I was browsing Abxzone, I saw a couple of comments (URLs
    got lost along the way). One was, disk corruption off the Via
    interface at about 228MHz. And, if somehow you can get the lock
    to work, there was a comment that you can lift HT to 280MHz on
    a rev 1.

    Even if the BIOS shows the above entry, there is really no way
    to know whether it is working or not. A PCI card called the
    "PC Geiger", a product from ioss.com.tw, can actually measure the
    PCI clock rate, but those cards are not widely available.

    You might get a copy of this tool. There is a version for
    the A8V, and even if you choose not to use it to set the clock
    rates on the board, it is possible the interface will identify
    the current value of the PCI clock. If it reads 33.0 MHz no
    matter what HT(FSB) clock you select, then the lock must be


    Paul, Mar 6, 2005
  13. CapeGuy

    Highlandish Guest

    thanks again
    Highlandish, Mar 6, 2005
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