Summary: Nice upgrade from the Core 2 Duo CPU, and has extended the life of an older setup. It has served as an inexpensive upgrade that has staved off a major purchase for at least another year or two (next step would have been motherboard, cpu, and RAM, which would have cost me 4-5x what this CPU did). If you're upgrading from a Core 2 Duo cpu, do yourself a favor and upgrade to at least the stock fan of the Core 2 Quad CPU.
Summary: This LGA 775 chipset is fantastic. I upgraded from a E2180 and can tell a difference. I'm using it with an Asus P5N-D motherboard. However, if your looking for stable overclocking and hardcore gaming on a budget (be mindful of your motherboard and PSU when overclocking) get a Wolfdale E8600. Wolfdale is the code-name for the E8000 series of Core 2 Duo desktop processors.
Summary: This processor is a great way to upgrade a Core 2 Duo motherboard without going all in for an i5 or i7 processor. On my Windows 7 machine this processor has greatly improved performance of Adobe Photoshop CS6 and Photomatix Pro 4. That said, the stock cpu cooler is junk. I put on an aftermarket cooler and it works much better.
Summary: The processor was a good bang for the buck upgrade, now the system is maxed out on processor and ram. It's strange to see a system become more efficient with more processor cores when it comes to the electric bill, but it was! It has helped with many projects I work on and a temp solution until I can build a quality 3rd Gen i7 system with a couple of nVidia cards.
Summary: The performance of the Intel Core 2 Quad Q9450 was better than the ol' familiar Q6600. This, of course, was the expectation going into the testing. In the scientific benchmarks, the Q9450 pulled out ahead in 20 out of 35 tests. While that does not seem like a world beater, 9 of the 35 tests were drive related and the expectation is that no change would happen. So taken as 20 out of 26 tests, this looks a bit better.
Summary: Excellent processor. Overclocked to 3.2ghz no problem using a standard intel heatsink and fan. 12mb for the q9x50 vs the 6mb for the q9x00 is very nice. improved WPI score of precessor and ram(probably has more to do with timings). replaced a dual core e8300. much better at multitasking now.
Summary: This is one of best CPUs that will go on a socket 775 motherboard. Many listings claim to be the best configuration, the q9000 series really has it! Speed and a HUGE 12Mb level 2 cache on a 1333Mhz bus make this an amazing processor. Make sure your bios will recognize/support this before you buy! Check your power supply as well, you can never be too careful. Surprisingly my system and my graphics card are now running cooler.