AMD OPN made simple

I finally decided to buy a T-Bred B to replace my obslecent Duron Morgan 1GHz ( OCed to 1250MHz @ 166 x 7.5 ) I did my homework and thoroughly searched the web ( no pun intended ) Here is what I found :

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It's a very informative page on the AMD CPUs OPN that go deep into the last and most interesting stage of the CPU manufacturing process, the marking.

For those too lazy to click it, here's the juiciest part :

<font color=red>Edited</font color=red>
Now is the most important part of choosing a good Thoroughbred:-

Examples :


The digits "26" and "28" actually carry certain meaning.

You might be able to guess it already. In our opinion after reading more than 50 personal reviews of Thoroughbred is:-

"26" means it is a downgraded version from 2600+ Thoroughbred.
"28" means it is a downgraded version of 2800+ Thoroughbred.

Believe it or not, those CPU with "26", "27" or even "28" tested to be stable at that particular speed with default voltage 1.65v, or even 1.525v which is fantastic !! That's why they run much cooler at extreme voltages, and can be overclocked to high speeds up to 3000+ (2.4GHz).

In General, assuming that:
24 = 2400+ 2.0GHz 266FSB
25 = 2500+ (should be a <font color=red>2.5</font color=red>GHz Thoroughbred with 266FSB but it does not exist!!)
<font color=red>Edited : should be 2.066, not 2.5</font color=red>
26 = 2600+ 2.083GHz 333FSB or 2.13GHz 266FSB
27 = 2700+ 2.17GHz 333FSB
28 = 2800+ 2.25GHz 333FSB
30 = 3000+ but not exist!!!

<font color=red>Edited...</font color=red>

There are rumors that AMD re-stamped the markings of some high-speed CPUs to fulfill the huge demand for lower-speed ones (mostly 1700+ and 2100+), if this is your case, then the CPU should be able to work stable at least 2400+ with the default voltage. I think it firstly concerns AMD Athlon XP “Thoroughbred” processors with B0 stepping that have much higher overclocking potential compared to A0 chips.


These 2 digits are the laser marker ID and used for chip tracing according to a friend who works in AMD Singapore Fabs.

Maybe those CPU with one particular code for example 24 was originally designated to be made for 2400+ model.
But due to failure of achieving that speed, it will be remarked to lower model. So whether that CPU can hit 2400+ or not with default voltage doesn't help...cos it has a great chance that won't run at that speed with default voltage at all..

We should treat these 2 digits as for reference only, because not 100% of the 28 chips can run at 2800+ !!
Bear in mind that the maturity and purity of wafer also affect a lot in performance. Coding will be the 2nd consideration after confirming which core is better by your eyes... o ryour 6th sense..

It was revealed that even if the information is misleading, the processors worked fine at the “initial” speed with Vcore increase.

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An Athlon XP/Thunderbird Processor Identifier, just enter the OPN "et voilà" !

Sorry for the long post but I'm sure it will be helpfull to a lot of us...

Fok Speling Misstake
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More about made simple
  1. GREAT!

    That indentifier script was already known to me but it doesn't work when you don't have all CPU information.
    But that guide is superb... and that colour thing is really interesting. If that also counts for Palomino's I got myself one heck of an OC'able Palomino (mine is grey in colour). Which confirm with my current findings as it is running 350MHz above stock with default voltage.

    My dual-PSU PC is so powerfull that the neighbourhood dims when I turn it on :eek:
  2. Just to keep you up to date, I managed 2313MHz ( 185 x 12.5 ) out of my 1800+ Tbred-B using Samsung TCC4 PC3200 @ 2.5/3/3/5 1T on a A7V333 v1.01 with BIOS 1016.

    Here's the OPN :

    AXDA 1800 DUT3C xxxxxxx 28 0499
    JIUHB 0307 SPFW

    I hidden the serial # in case something go wrong and I need to RMA it...

    I'm now running it @ 2000MHz ( 166 x 12 ), memory @ 2/2/2/5 1T, been running Prime95 torture test for quite a while now.

    Fok Speling Misstake
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