Asrock K10N78FullHD-hSLI R3.0 slowing RAM

Hi all - first post here for a long time but I'm puzzled by my new build and wondered if anyone could explain something to me regarding an AMD system's FSB : DRAM ratio.

My new system:

Asrock K10N78FullHD-hSLI R3.0 (spec here)
Phenom 9650 triple core
4 sticks of unbranded 2Gb DDR2-800/PC26400

Okay, I know I shouldn't have cheap RAM but it's a long story! - I had a nightmare with an Asus M3N78-VM (check out their forums for many people having POST/memory problems) and ended up borrowing/acquiring loads of RAM for testing... eventually ditched it and this board is a God-send by comparison but I only have cheap RAM left at the moment.

Only thing that's getting me is that CPU-Z is reporting that the memory's running at 200Mhz with a FSB : DRAM ratio of 1:1. Afraid I can't screengrab it at the moment as I'm at work, but that's what it's showing.

This is confusing me because the same RAM in the Asus M3N78-VM reported as 400Mhz with 1:2 - just like the bottom CPU-Z screengrab in this page.

I have manually set the DRAM speed in the BIOS to "400 (PCII-800)" and during POST it reports it as such.

I am wondering why the RAM is reporting as 200Mhz and at a 1:1 ratio? Is this normal for this board/memory?

I have 8Gb in at the moment and it's all very stable during games with a 9800GT, but I will try going through it stick by stick later tonight. I am not bothered about having 8Gb long-term, just trying to figure out this ratio thing and make sure the RAMs running at proper speed.

I'd appreciate any general explanations about the FSB thing because this is my first build for about 4 years and technology has moved on without me!

Thanks very much for any hints as even looking on the Wikipedia DDR2 page just confuses me more