After that, look for a guide for your specific motherboard.
Go through the guides. Then take your core voltage off Auto and set your memory voltage to factory recommended values. Change the System Memory Multiplier (or whatever your BIOS calls it) from AUTO to 2.00, 2.00B, or 2.00D - whichever you need to set the Memory Frequency to twice the FSB. Then when you increase the FSB, the memory clock will rise in in proportion with it. At an FSB of 266 MHz, your memory clock should be at 533 MHz.
Download CPU-Z to check your FSB:RAM ratio. It should be a 1:1 ratio.
Warning - there may be a confusion factor between what the BIOS calls things and what CPUZ calls things. What the BIOS calls "memory frequency" is actually the memory clock. What CPUZ calls "memory frequency" is half the memory clock - DDR2 RAM, remember? It transfers two chunks of data each bus cycle. What you want in CPUZ is a 1:1 FSB:RAM ratio.
what case are you using? I used the Cooler Master Hyper 212 Plus in a Cooler Master Storm Scout case, and I had to remove a side panel fan. I just added it to the CPU cooler for a push/pull configuration. I was very pleased with it. Just wanted to give you a heads up about possible clearance issues.
I use youtube alot, I'm a more visual person. Just search for your case and a cooler and most likely someone has done it and posted.
Wow, that Does look Rather nice...
Does the setup fit inside the case (I see the side panel is removed)?
And performance wise? would you recommend it? (Its not my choice my customer said he wanted this cooler specifically but i was thinking of buying one myself)
Yes, it fits fine with about 1/2 of an inch to spare, just not enough room for the fan. I'm very happy with the cooler. The CM storm case has the CPU cutout, which makes it easy to install the back plate without removing the motherboard.
I have a 955 BE @ 4.0 Ghz that tops out at 54c with OCCT linpack.