Benjamin Smith <lists at benjamindsmith.com> wrote: > Has anybody here taken a HDD configured with an Opteron > system, and then put it into an Athlon/64 and had it work? > Are they interchangeable, like an Athlon/32 and a P3/P4? Yes, to a point. An x86 system will _not_ boot a x86-64 kernel. But yes, a x86-64 system _will_ boot a x86 kernel. The x86-64 kernel puts the CPU into a 52-bit PAE memory mode. x86 systems only support a 36-bit PAE memory mode. For more, see my blog entry here: http://thebs413.blogspot.com/2005/10/what-is-x86-64-long-mode-memory-model.html The only other issues are boot-time storage support. Most [parallel] ATA devices are no issue, because they are in the stock ATA/IDE kernel support. SATA is a different issue, because many SATA drivers are SCSI block drivers at this point, so they need to be built into the initrd (initial root disk). Linux isn't like NT 5.x (2000/XP/2003), which sets boot-time information in the registry and will blue screen if you change mainboard/chipsets. Yes, not even changing the ntbootdd.sys file for the appropriate ATA/SCSI works (like it did for NT 4.0 and earlier). The only way to change that is to boot up another OS (e.g., Linux) with a registry editor and manually change the 3 or so keys for the boot-time storage device. -- Bryan J. Smith Professional, Technical Annoyance b.j.smith at ieee.org http://thebs413.blogspot.com ---------------------------------------------------- *** Speed doesn't kill, difference in speed does ***