Hello, All, Dave Jones sent out a patch about Pentium IV cacheline sizes, please refer to http://marc.theaimsgroup.com/?l=linux-kernel&m=100297450316163&w=2 to which Manfred Spraul responded http://marc.theaimsgroup.com/?l=linux-kernel&m=100299763026680&w=2 I think the patch is correct and should be applied. >From Pentium IV, System Programming Guide, Section 9.1, Page 9-2, Table 9-1. Order # 245472 L1 Data Cache - Pentium 4 and Intel Xeon processors: 8 KBytes, 4-way set associative, 64-byte cache line size. L2 Unified Cache - Pentium 4 and Intel Xeon processors: 256 KBytes 8-way set associative, sectored, 64-byte cache line size. The point is that according to the specs both L1 and L2 cacheline sizes are 64-byte. Comments, Balbir