JIUHB who ?
Most on-line vendors simply sell AMD CPUs by their Quantispeed rating. Each numerically higher rating attracts a higher price, naturally. XP1700s (1.466GHz / 133FSB) are currently the cheapest at around £45. XP2800s, however, will take a £300 wedge out of your wallet. That's a monumental price difference for processors manufactured via the same process. The key would be to obtain a low-priced XP CPU with the same standard of core as the more expensive variety.
AMD give each and every CPU certain codes that don't mean all that much to the average buyer. Those codes, once deciphered, can tell us a great deal about the origins and potential of a particular CPU.
Certain on-line vendors, though, specialise in acquiring and selling these hidden CPU gems. CPU City are one of these vendors. They openly state the stepping (the key to understanding which CPUs have the best potential) and you can specify it when ordering, thereby semi-guaranteeing a decent overclock. They were kind enough to send us the processor that should be the pick of the bunch if you're looking for a price-to-performance winner. Enter the much-vaunted AMD XP1700 JIUHB.
The devil is in the details. The first aspect to note is the rectangular core and sticker underneath. That's your guarantee that the processor's a Thoroughbred (0.13u) XP. The AXDA name verifies this fact. The outgoing Palomino (0.18u) had limited overclocking potential. The 1700 (1.466GHz / 133FSB), obviously, refers to AMD's Quantispeed rating. With the XP able to perform more work in a clock cycle than its main competitor, the Intel Pentium 4, AMD felt obliged to drop the MHz rating in favour of one that more accurately reflected its comparative performance.
The next section of code gives us a lot of information, all available from AMD's press sheets. Using AMD's literature with an XP2700 as an example.
If you want to understand what each letter of the code actually represents in numerical terms, have a read of this pdf file from AMD. That document tells us that the DL3TC codes on our chip refer to the OPGA packaging, 1.5v operating voltage, 90c max. temperature, and a 266FSB respectively. The 1.5v operating voltage is important; the lower the specified amount, the greater the likelihood of high MHz operation.
Whilst all the above helps in identifying a decent prospect, it doesn't guarantee you a high overclock. The initial alphabetical code on the second line is the one to watch out for. There are no hard-and-fast rules detailing which stepping (codes) will do well, it's more a case of enthusiasts reporting in to forums with their results. The only information we can take away from this portion of code is that this CPU uses the preferred Thoroughbred "B" core, as the code ends in the letter B. Looking at enthusiasts' results from a number of forums, it appears that XP CPUs with the AUIHB stepping tend to go a little further than those with the JIUHB stepping. Finally, the 0310W refers to the year (03) and week (10) of manufacture. The last portion of code is another of AMD's internal nomenclatures.
To summarise from the codes above, our test CPU from CPUCity is an XP1700 at default (1.466GHz / 133FSB) with some rather enviable properties. It's a Thoroughbred "B" core (preferred), with an operating voltage of just 1.5v. It also features a stepping that's known to do well. How well ?. Let's find out.
