HP H-IG41uATX Mother board works @ 1066 Mhz with single 2GB 1333 Mhz RAM

Hi,

My HP H-IG41uATX  Mother board works @ 1066 Mhz  with with  single 2GB 1333 Mhz RAM ( Apacer PC -10600 ) @ 7-7-7-20.

Bios  is Version 6.08 , 07/07/2011. Core Version - 08.00.15

Bios detected it as PC-8500. CPUZ  Shows it as PC-10700  working clock speed  @ 533 Mhz ( =1066 Mhz. DDR ).

Processor is Intel Pentium Core 2 Duo E 8400 3.06 GHz  with 1333 MHz FSB.

OS WIndows 7

1. Why The Motherboard capable of 1333 Mhz is not working @ full speed ?

2. A Memory working @ 1066 MHz @ 7-7-7-20  VS Memory working @ 1333 MHz @ 9-9-9-24 Which is better ?

Binil