Once mapped into memory, sections always start on at least a page boundary. That is, when a PE section is mapped into memory, the first byte of each section corresponds to a memory page. On x86 CPUs, pages are 4KB aligned, while on the IA-64, they're 8KB aligned. The following code shows a snippet of PEDUMP output for the .text and .data section of the Windows XP KERNEL32.DLL.
Section Table
01 .text VirtSize: 00074658 VirtAddr: 00001000
raw data offs: 00000400 raw data size: 00074800
•••
02 .data VirtSize: 000028CA VirtAddr: 00076000
raw data offs: 00074C00 raw data size: 00002400
The .text section is at offset 0x400 in the PE file and will be 0x1000 bytes above the load address of KERNEL32 in memory. Likewise, the .data section is at file offset 0x74C00 and will be 0x76000 bytes above KERNEL32's load address in memory.