Interesting, so in terms of achieving performance, I am to orientate my efforts all on getting the lowest PL value?
And the timing and clocks are just the means/'tools' to get me to tweak ever closer to the lowest value of PL possible right?

usually 4:5 or 3:4 or 5:6 can achieve lower PL, so even at looser timing, it still perform better..
This is really interesting... I have my FSB set at 400, Strapped at 333, I can achieve 1:1.2 by increasing my DD2 from 800mhz to 961mhz.
Can someone clarify me this, is 1:1.2 technically 5:6? Mathematically 5:6 is 1:1.2( 5/5 = 1 : 6/5 = 1.2) but probably a totally different thing in computing i guess...

What other means I can attain stability in getting the lowest value of PL?
FYI, ATM I set my PL @ 10. I'm using Asus P5Q Turbo btw, Any suggestion that I can get lower PL?
Ai Clock Twister?,etc.

Alright, I manage to lower the PL to 7, the comp will not POST at 6.
I have my divider set @ 4:5. My guess is, i need a tighter timing on the DDR2 (4-4-4-12) to get lower than PL 7, but since my ram is 5-5-5-15 setting it to 4-4-4-12 causes the system to be unstable, hence will not perform POST. So I'm sticking with 5-5-5-15 ATM.

But to make up for the inadequacy, I manage to set the Ai Clock Twister to 'Moderate' and running it stable, will try 'Strong' later.
Here's the benching result of before and after OC'ing the system performance:

Before: (PL 12, 1:1 ratio, Ai Clock Twister on Auto and 800mhz clockspeed of ram)
[attachmentid=1353497]

Current (13/12/09): (PL 7, 5:4, Ai Clock Twister on 'Moderate' and 1000mhz clockpeed of ram)
[attachmentid=1353498]

As you can see the latency is lowered noticeably. I'm still working out on how to get the latency below 56ns, so I'm going to play around with the ratios that PL and getting the ram to stabilizes under 4-4-4-12 setting by bumping up the vDimm/vDDR or by other methods.

Hope anyone kindly can show me how you get the PL at 6, or best at 5 

I don't know if my KHX6400 (800mhz) Kingston HyperX use elpida or them D9's, I think they used to use d9's, but will research my rams more, the problem is I don't know where to start looking..

As for the vMCH/vNB, the heatsink on the NB felt warm and borderline-hot when I juiced it up to 1.26v..
Since I'm pretty new to vMCH fiddling, can you recommended me what range of vMCH is good for 'safe' NB OC'ing? (on Asus P45 P5Q series MoBo)

And do you know more on 'Ai Clock Twister'? I know it sets the Dram performance-to-compatible perimeter, but what does the Overclocker's society take/views on that 'Ai Clock Twister'?