Athlon Versions

My Athlon Thunderbird core A0900AMT3B on my DFI AK 74-EC
(100FSB w/2Xmultiplier) crapped out on me so I borrowed a friend's Duron D900AUT1B. The Duron runs like a champ but I have to give it back.

Notice please that both have the "B" cores. I went to a couple of computer stores locally and asked if they had any more CPUs with the "B" core. Most of them were :smile: :smile: :smile: :smile: :smile: !!!

You have to understand that the "B" core is hard to come by in stores nowadays because most of the ones I went to don't have them anymore. Either the T-bird 1333 in this case 133FSB or the Athlon XP (478). My question is will the T-bird "C" core work on my mobo with 100FSB?

CPUs aren't backwards compatible are they? I mean an Athlon w/133FSB won't lower to a 100FSB mobo will it?

I'd love to get this rig running again.



<b><font color=blue>veni,vidi, and ended up in THGC<font color=blue></b>
13 answers Last reply
More about athlon versions
  1. I found a 1.0GB Athlon with the 133FSB. Mounted it on my current mobo and it boots XP. Problem is, in the BIOS it recognizes it as a 750Athlon (100x7.5). Is there any way of getting the actual 1Gig out of it? Tried the multiplier in the BIOS but that's not working. Do I have to UP the core voltage?

    At least it's running again.

    <b><font color=blue>veni,vidi, and ended up in THGC<font color=blue></b>
  2. As far as I know all Athlon thunderbird processors from 1.2 to 1.4ghz were released multiplier unlocked. Therefore on a 100mhz motherboard you should easily be able to bump them up to their correct speed or higher providing the multiplier values are available. For example a 1.4gig thunderbird 133FSB x 10.5 alternatively 100FSB x 14.0.
  3. Thanks,

    I'll have to try it out.

    Let you know if there's any improvement.


    <b><font color=blue>veni,vidi, and ended up in THGC<font color=blue></b>
  4. Yes I'm not sure that the particular chip you're using is multiplier locked. But if it is your motherboard won't be able to change it (which sounds to be what's happening to you now). You can unlock it quite easily though using an a graphite pencil and shorting the L1 bridges there are plenty of articles on here that show you how.
  5. U coulda got ANY Duron CPU on the market and u would have been fine.....

    as far as the 1GHz Athlon with the 133FSB.....if it is NOT Multiplier unlocked from the factory, what ur gonan have to do is take otu ur CPU...look for the little gold bridges on the ceramic f the the L1 bridges r what ull need to connect, they will either look like this : : : : or they will look like this | | | |....

    : : : : = LOCKED
    | | | | = UNLOCKED

    to make it UNLOCKED u have to Fill in the four L1 bridges with a pencil...i find a mechanical pencil works the easiest.......than when u boot up the computer...go into the bios and change the Multiplier from 7.5 to 10.0....

    My OTHER question to u as i know nothing about ur motherboard, is, does it support the 133Mhz FSB Setting.....cuz if it does...why r r tryign to force it to run at 100Mhz FSB??

    as far as backwards compatibility...yes it sure is......

    <A HREF="" target="_new">-MeTaL RoCkEr</A>
  6. Nevermind, i looked up some info. on ur Motherboard and its the KT133 VIA Based only 100(200Mhz DDR).........anyways hope u get ur 1000Mhz T-Bird running ok..........the other problem u will have with ur motherboard is running it at ur board does NOT support Multiplier adjustments...which means in order to get ur CPU to run at 1000MHz...not only will u have to do more than just change the L1 bridges.....most likely the L6, L5, L3 and L4 and L2 also............u have to change all the bridges in conjunction to make it seem as if its an authentic 1000MHz 'B' Type Thunderbird........

    If u want info on how to do this...look on toms hardware guide through a few of there very first articles on the AMD Athlon on Socket A or the AMD Duron...there VID, and FID Charts that show what the settings r for each L4 & L5 etc. bridge for what multiplier and each setting....u gotta chaneg ur chip from what it is (which will represent 750Mhz on that chart) to 10.0 (which will represent 1000MHz on those charts) anyways i hope u understand what i mean...and good luck...........

    <A HREF="" target="_new">-MeTaL RoCkEr</A>
  7. Metalrocker, I was afraid I'd get an answer like yours. That's what I was thinking also. Without doing anything to the CPU I did manage to get it to run stable at 802Mhz. In the BIOS I ran the 'CPU Host/PCI Clock' setting at 107/35Mhz with 1.750 Vcore voltage. When the settings are at DEFAULT, the CPU is recognized at 750Mhz (100x7.5) on POST. Seems to be running stable. This CPU is according to the DIE is an Athlon A01000XXX1C.

    If I up the voltage and go to the next stepping, is there a possibility of frying the CPU? The CPU I have in there now has locked L1 bridges. I even went to XP's System Information and checked to make sure it recognized the CPU @ 802Mhz and it does. Otherwise I wouldn't be answering your post.

    Also I'm using VIA Monitor to check the CPU temperature and w/SETI running in the background, I'm at a reasonable 33C/91F. My HSF is clocking around 6100rpm so heat shouldn't be a problem. Got twin Sunoi 80mm in front sucking air in and another 80mm Sunoi as exhaust. Ambient is 28C/82F and a 300W PSU so there should be no problems.

    I'm not trying to OC this rig. I just want to get it to where the CPU is rated at even if it runs only at 100FSB (200DDR)

    To save me the trouble, I could:
    A: get a new Mobo that'll handle the CPU.
    B: get a Duron 1200 with 100FSB.
    C: get an Athlon 1200 with 100FSB
    D: proceed w/ your suggestion about modifying all the bridges.

    ThanX Metalrocker and Bronibbear

    Metalrocker, you clarified a couple of my suspicions.


    <b><font color=blue>veni,vidi, and ended up in THGC<font color=blue></b>
  8. It might be advisable to take that your CPU back (assuming that you bought it from a shop) and exchange it for an Athlon thunderbird 1.2 upwards it will cost you a bit extra but would be well worth it not only for the extra performance but the fact that these processors are definitely factory unlocked! It will not matter if they're type C processors as they will run happily with a 100FSB and allow you to compensate with a higher multiplier setting in your bios without any modifications to the chip. I wouldn't recommend you get a Morgan core based Duron for although in theory it would work fine with older motherboards my experience has been to the contrary. I tried to upgrade a friend’s old system with one of these and although it worked it caused constant instability probs. On looking up the motherboards manufacturers website I was shocked to find that the particular mboard we were using could not properly run any AMD CPUs with Morgan or Palomino cores (Duron 1ghz up or Athlon XP) due to subtle differences in the core architecture as compared to the Spitfire and thunderbird cores (old Duron up to 950mhz and Athlon thunderbird up to 1.4ghz) which it was made to run with! We ended up changing it for a Thunderbird 1.2 and his computer has never looked back since! The other alternative if you want to try it is to unlock the L1 bridges of your current CPU you shouldn’t need to increase the voltage settings as you're not going to overclock it. Here is a link to the best article I know of for doing this to date.
  9. I can't take it back. German vendors are quirky when a package has been opened. The only possibility is getting a Mobo that'll use the potential of the CPU. It'd be a waste to keep it running at 750.


    <b><font color=blue>veni,vidi, and ended up in THGC<font color=blue></b>
  10. I can't take it back. German vendors are quirky when a package has been opened. The only possibility is getting a Mobo that'll use the potential of the CPU. It'd be a waste to keep it running at 750.


    <b><font color=blue>veni,vidi, and ended up in THGC<font color=blue></b>
  11. Ok dude......copy this down or print this post of mine out for you.......u want your chip to work at 1000?? this is how u do it.....

    L6 - : | | :
    L3 - : | | :
    L4 - | : : |
    L7 - | | : | | - (1.75 Core Voltage)
    Thats how it is right now correct?? That that default for either a 750MHz Duron/Athlon T-Bird OR a 1000MHz T-Bird with 133Mhz 7.5 X 133 = 1000..... and 7.5 X 100 = 750 which is why its detected as a 750 in your system.....LEAVE THE L7 ALONE.....U do NOT need to modify it in anyway.....voltage in bios or jumper/dipswitches should also be left to DEFAULT.....

    TO MAKE 1000MHz:
    L6 - | : : :
    L3 - | : : |
    L4 - : | : |
    L7 - | | : | | - (1.75 Core Voltage)

    as far as making the L1 bridges from : : : : to | | | | it wont matter in this case as your actually modifying the CPU to make it think its got an internal multiplier of 10.0 vs 7.5........the L1 would go from Bios to CPU back to MB if u adjust the multiplier in bios or jumpers.....this way makes the CPU an "authentic" 10.0 using Multiplier CPU...

    To connect the open/cut bridges use a sharp pencil like a mechanical pencil..also make sure u do not make the lines touch wont damage ur chip but it may cuz the computer to NOT for CUTTING some of the bridges......try going across the bridge firmly with a very sharp Exacto Knife(sp?) or something similar like a sharp scalpol(sp?).........anyways I hope that helps...otherwise ur gonan need to pick up a new motherboard......

    <A HREF="" target="_new">-MeTaL RoCkEr</A>
  12. Thanks metalrocker,

    A very concise explanation and correct to the T! I did go to Tom's article "Overclocking AMD's Socket A Processors" and read up on it. I even went to Anandtech.

    Anyways, I appreciate the thorough answer and I did print this whole post for future reference.

    Vagabond :smile:

    <b><font color=blue>veni,vidi, and ended up in THGC<font color=blue></b>
  13. Awesome!

    I hope it helps you out......good luck =)

    <A HREF="" target="_new">-MeTaL RoCkEr</A>
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