Storage fundamentals: misaligned blocks
All Windows versions before Windows Server 2008 may have misaligned windows blocks when provisioning storage.
Intel´s MBR writes 63 sectors at the beginning of the disk. Let´s say the LUN has been formated with NTFS 4 KB blocks. The last and the first 4 KB (ntfs) block of each block on the LUN (for example 64 KB blocks) will cause disk crossing.
This means for reading/writing to disk 4 KB block two disk reads on the storage are needed and this has an performance impact!
note: this problem may also occur on other operating systems
Use diskpart to align the blocks correctly starting at 1024:
select disk x              // select the appropiate disk
create primary align=1024