Which ram? Mbp 17" 2.3

[getheo]

Which ram should i choose?? Are there any differences??

1. KHX1600C9S3K2/8G

http://www.amazon.co.uk/Kingston-16...7B60/ref=sr_1_1?ie=UTF8&qid=1313832057&sr=8-1


and

2. KHX1600C9S3P1K2/8G


http://www.amazon.co.uk/Kingston-Hy...XAAK/ref=sr_1_1?ie=UTF8&qid=1313832250&sr=8-1