Breaking Intel's Overclock Lock: The REAL Storyby Wesley Fink on July 16, 2004 3:39 PM EST
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IndexSince the first reports of Intel's overclock lock, the web has been buzzing with speculation about what Intel did and how to fix the lock. There has been so much misinformation, partial truths, and downright confusion regarding the lock that it's time to set the record straight.
Asus and Abit have been most successful so far in finding ways around the lock, so we spent some time with both companies to determine what they have found and how they are bypassing the lock. How do we measure success? It is simply a matter of performance. Abit has managed to produce a 925X that is capable of a 258 CPU Frequency.
Asus has enjoyed even more spectacular success. With their latest BIOS revision 1.04 and higher, Asus is now reaching our CPU limit of 278-283 CPU frequency. This is confirmed with a SATA hard drive and PCIe video card, since you will see there is much more to the story than Northbridge voltage.
Yes, Virginia, There IS an Overclocking LockThe overclock lock is very real on the Intel 925X/915 chipset. Sources close to Intel have confirmed that the 925X/915 chipset was designed with a 10% overclock limit as a design parameter. This is not a simple lock loop, but involves several components according to Engineers at Asus and Abit:
- PCI Express floats in the Intel 925X/915 chipset. PCIe frequency exceeds the capabilities of PCIe cards at about the 10% overclock level. Neither Asus or Abit or any other manufacturer that we have talked with has been able to effectively lock the PCIe frequency in the new 925X/915 design. This is the major roadblock to overclocking on the 925X/915, as any attempt to lock the PCIe frequency limits overclocking.
- The Northbridge and Southbridge link frequency also floats with the CPU frequency, and since link frequency is monitored at startup, values higher than 10% cause system shutdown. It is true that increasing the voltage to the chipset increases tolerance in this area, but you only gain about 10 MHz to 15 MHz by applying voltage (CPU frequency can increase from 220 to 230 to 235), since the PCIe and SATA issues are not corrected.
- SATA must be fixed at 100 to function, but the SATA frequency is also influenced by the link frequency. SATA drives simply disappear when the link frequency exceeds the 10% overclock. This can be extended with a bit of voltage, but voltage is not a fix for this issue either.