I really don't understand this blind need for pure Ghz as the holygrail for bragging rights at 3.5-3.6+ and beyond. Frankly, I am a realistic and practical guy when comes to overclocking - real world FPS on real games with similar emphasis on both memory bandwidth and memory timing. Before I get into my philosophy for overclocking, here are my results:
$299 OEM Q9450 C1 stepping 3.334Ghz stable @ 1.168 V stock voltage on EVGA 690i Ultra. Bus Speed 416.7Mhz, CPU FSB 1667Mhz. OCZ Reaper HPC DDR3 1333mhz 6-6-6-18 timing, 2GB - $143 after rebate on Newegg.
These have gone through many hours of prime and torture test as well as multiple pass of Supreme Commander and Supreme Commander Forged Alliance /perf test. I also ran Crysis test, all passed without a hiccup.
My highest post is 4.0Ghz. My highest windows xp pro install and boot stable is 3.6Ghz but not at stock voltage of 1.168 V and I didn't want to go beyond stock voltage.
My philosophy: CPU and RAM duality, Stock Voltage, Memory timing, CPU FSB to Memory ratio, Price, Timing Entry for Upgrade
If you got a nice Q9450 to 3.6Ghz~4.0Ghz but without a fast memory (ample bandwidth and timing) feeding it, your overclocked CPU is worthless, just idle waiting for data. What's worst, if you increase the voltage such as that xpose guy to 1.45V, you're doing yourself a great disservice as killing your lifespan of such a longevity CPU for years to come is nothing to be proud of. Logic dictates the higher you go on voltage, more cooling, gives you higher clock. But why at the expense of killing your CPU? Eventually developers of OS, games, and applications will optimize the use of your Quad and you're just overheating, electromigration cross jump due to super high voltage and killing it, possibly making it slower as it is jittering and dies during it inevitable decline to its death. Not to mention stability issues and a lifetime of headache.
Second worst thing is some try to go all out on memory bandwidth (pure Mhz, like 800mhz 1066mhz on DDR or 1600mhz/1800mhz on DDR3) and care nothing about MEMORY TIMING. I really shouldn't get into all the details as you should be doing the research yourself but let me just say in rough equivalence: DDR3 1333 6-6-6 is similar in linear performance as DDR2/DDR3 1100-1200 5-5-5, DDR3 1600 7-7-7, DDR3 1800 8-8-8, DDR3 2000 9-9-9. So if you only brag you overclock your DDR3 to 2000mhz but have 9-9-9 timing, it's basically the same as 1333mhz 6-6-6 timing in random read, random write game performance. Real world FPS will show you, not only is your system LESS stable but performance will suffer greatly when you ignore TIMING altogether. The difference between a 1800mhz DDR3 2G Ram between a 7-7-7 and 6-6-6 timing is like from $300 vs $600 US Dollars. Just for that little timing jump? Well, yeah, because true gamers UNDERSTAND what they're paying for and can visually tell in real world FPS.
CPU FSB to Memory ratio. I always try to put in some kind of a definite ratio 1:1, 1:2, 2:3, 4:5 or any reverse combination of those. Doing so gurantees the efficiency of data queue in pipelines, especially with such a large 12MB L2 cache. I am a Cisco CCIE Voice engineer, in QoS (Quality of Service), I study traffic policing and traffic shaping. I believe the buffering and queueing of data in pipeline must be efficient for the overall working performance of final delivery output.
Price. I make good money in real life so if I wanted to I would just buy the best pre-built extreme system, a power desktop with a $5,000 budget. But that would defeat the purpose and the spiritual meaning behind the enthusiastic market. Speaking of price, I probably could get a $59 Abit mobo and sub $100 Gigabyte for DDR2 solution but I did not because I'm not dirt poor and we're at a time of transition where I can see the light at the end of the tunnel for DDR3 as prices has come down a lot and performance are ever increasing. Investing in a motherboard supporting only DDR2 memory is killing your long term potential for Q9450 Penryn 45nm CPU. Why 2GB not 4GB? 4GB with 4x1GB sticks introduce timing latency introduced inherently that most do not talk about. So 2GB is mostly for gaming performance. Future upgradability, I didn't want to cap myself at 4GB RAM. Leaving the extra 2 slots, enable me to upgrade to 6GB or 8GB if I sell my DDR3 1333mhz 6-6-6 timing on Ebay later.
Let me summary my joy of this current system with one sentence:
I got a $299 Q9450 OEM cpu that out perform a $1,600 QX9770 Extreme cpu on stock voltage at 1.168 V using air cool only Zalman 9700 & Antec 900 gaming case.
Timing Entry for Upgrade. There is always the best time and worst time for upgrade. Worst time is 6 months ago, when DDR3 are still too expensive, DDR2 1200 5-5-5 timing was super cheap, it's just not there for the jump. Regular Penryn Quadcore Q9450 aren't really available yet, esp. C1 stepping ones. So the entry is now (April 15th 2008 & beyond), this is the beginning of a long term future for DDR3 and price entry is acceptable. This is just my opinion based on 20+ years of overclocking experience and maximizing bang for your buck.
Other thoughts:
At stock voltage of 1.168 V, I am able to run FSB 1666mhz, 66mhz higher than the stock FSB of the QX9770. Could this be a fluke? Like Intel basically cuts off the maximum QX9770 it'll produce even though they can but decide to mark them signifiancaly lower as a Q9450 OEM aftermarket? Maybe. I can't say because I do not have a 6-6-6 timing super RAM @ 2000mhz DDR3 nor do I really want to at this point. I'll keep running on stock voltage 1.168 V for years to come and if one day, I need more CPU performance, I'll buy something like even better than QX9770 processor, extreme edition, and overclock it to 5.0Ghz or higher Quad Extreme possibly with 24MB L2 cache on the same motherboard. When DDR3 price comes down and can overclock beyond 2000mhz with 6-6-6 timing or lower, I'll jump on it again, on the same motherboard.