Mobile = potential
Just a regular Barton XP2500+, eh?. Sure looks like it. The same packaging. The same kind of codes on the rectangular black section underneath, and no obvious clues as to its mobile status. Careful examination of the codes contained on the black strip does reveal that it's no ordinary desktop Barton.
AMD's processor recognition file for Athlon XP files can be found here. It provides us with the keys to decipher the various letters and numbers contained directly under the Barton core. We'll do the hard work for you. The first line is the most important.
AXMH - Denotes that this is is indeed a Mobile AMD Athlon XP CPU, based on a 0.13-micron manufacturing process. That narrows the possible CPUs immediately.
2500 - The model number, in this case a 2500+ or Barton CPU.
F - The type of packaging. F denotes OPGA (Organic Pin Grid Array)
Q - An important letter. It denotes an operating voltage of 1.45v
Q - Maximum die temperature. No figures are given in the pdf file. We can assume it's somewhere between 65 - 85c.
4 - Denotes the amount of L2 cache. 512KB here. It's a Barton. No doubting that.
C - Relates to maximum front-side bus speed. The literature contends that C translates to a 133MHz FSB. Desktop Barton XP2500+s are all run off a 166MHz FSB. That's the one notable difference. It seems as if it's up to notebook designers to choose the desired FSB. That in turn leads us to believe that these CPUs are unlocked, unlike the very latest desktop processors.
The second line denotes the stepping, AQZFA, week of manufacture, 40th week of 2003, and a further code that is sometimes useful for guaranteeing an overclockable CPU. To sum up, we have a mobile 0.13-micron AMD Athlon XP-M Barton 2500+ CPU that operates at a nominal 1.45v. The packaging also denotes that this CPU is intended to be used in full-size notebooks. Thin-and-light laptops often use a uPGA (denoted by the letter G). All Mobile Barton CPUs implement PowerNow technology. The technology allows compliant motherboards and OS' to modulate the power requirements in times of load and idleness - all in an attempt to increase battery life.
We want to investigate if these deskop-sized Athlon XP-M Barton CPUs can be used in desktop boards without any problems. If they can the low operating voltage is sure to raise the eyebrows of enthusiasts. Intel's mobile Pentium 4s, though, all tend to default down to a 12x multiplier in a desktop environment. That makes overclocking, especially of the 133MHz FSB variety, a difficult task. One often runs into front-side bus limitations before hitting the MHz ceiling.
And the results of our testing was..........