Ars Technica heeft een artikel gepost de frequency lock en hoe Intel die op z'n CPU's zou kunnen bouwen. Er staat ook nog wat info in over de werking van de multiplier lock en Tom's #B21 trick. Ook wel interessant is dit stukje over de overclock protectie op de Xeon:
Intel has a pretty sane way of providing the consumer some protection against buying remarked, overclocked Xeons. Each Xeon has a processor information ROM (PIROM) built into the processor substrate. This PIROM is electrically programmed at the factory to hold details about the chip’s core type, core stepping, etc. There are 16 bits at offset 16h in the PIROM that store the processors maximum core frequency (in MHz). So if you want to know what the speed your Xeon was rated at, just check that number.
It seems to me that if Intel is as serious about stopping illegal overclocking as they are about robbing every last shred of privacy from their customers, then they’d just do something like this with the PIII, instead of that ridiculous CPU serial number.
Als Intel het remarken van z'n CPUtjes wil voorkomen dan lijkt me de bovenste methode het eenvoudigst. Overklokkers kunnen dan gewoon hun gang blijven gaan, maar vervalsingen komen meteen aan het licht...
Verder nog wat stuff over de bus lock:
97%>I personally don’t think "bus locking" will ever really be feasible. By a "bus locked" processor, I mean one that simply won’t operate above a certain core frequency. The problem with locking the bus frequency is straightforward: today’s CPUs really don’t know at what frequency they’re operating. They simply have no way of telling. They just operate at some multiplier of whatever frequency they get on their BCLK pin. If you want to bus lock the CPU, you’ve got to add circuitry to it somehow to detect what the current bus frequency is and stop the presses if that frequency exceeds a certain amount.