I purchased this processor from a local retailer for 9 and it has been great. It is paired with a Gigabyte ga-ep45-ud3p, 8gb pc6400 ddr2 ram, and a NVIDIA gt 240. My machine is incredibly fast at stock speeds, and still faster yet when overclocked. I use Linux Mint 9 x64 and the combination of OS with this chip is lightning fast. The 12mb l2 cache makes a big difference and this is essentially the same chip as the q9650 (.17 ghz lower clock speed). Do yourself a favor and save 0 by going w/ the 9550. I keep mine o/c'd to 3.2ghz and it idles at 30 degrees celcius while never going above 43 under load. I have heard this cpu is capable of 3.4-3.6ghz on stock voltage and higher with voltage increase, but I have not pushed it past 3.4, whereupon it ran cool and stable.
Product Description:Intel Core 2 Quad Processor Q9550 2.83GHz 1333MHz 12MB LGA775 EM64T CPU
Amazon.com Product Description:Amazon.com Product Description Four computing cores in a single processor give multitasking users the ultimate edge in efficiency and performance—no matter what software application they are running. With a quad-core processor featuring Intel's revolutionary new 45nm architecture, multimedia experiences are faster and more responsive as video transfers, image rendering, data compression, and intense gaming applications are streamlined to process seamlessly with remarkable speed. As a result, demanding users can accomplish more in less time.
Amazon.com Product Description
Four computing cores in a single processor give multitasking users the ultimate edge in efficiency and performance—no matter what software application they are running. With a quad-core processor featuring Intel's revolutionary new 45nm architecture, multimedia experiences are faster and more responsive as video transfers, image rendering, data compression, and intense gaming applications are streamlined to process seamlessly with remarkable speed. As a result, demanding users can accomplish more in less time.
Intel® Core™2 Quad Processor Product Highlight
Starting with Intel's revolutionary new high-efficiency, high-performance 45nm processor technology, Intel engineers decided to go one step farther in the performance department. By including up to 12 MB of shared L2 cache and Front Side Bus speeds of up to 1333 MHz, the Intel® Core™2 Quad processor pushes the technological innovation envelope farther than ever before. For users, this means the latest and most advanced software applications can open and run faster than ever before with superior responsiveness. When used with the latest multimedia software and next-generation games, dropped frames, long waiting times and stuttering performance are history.
Intel Technology 45nm Hafnium-Based Architecture. Thanks to a naturally occurring element called Hafnium, Intel engineers were able to shrink the size of new Intel processors and pack more computing technology into less space. The result is improved performance with less energy wastage.
Intel® Wide Dynamic Execution. Enables the delivery of more instructions per clock cycle for shorter execution times and improved energy efficiency—accomplish more simultaneously and with greater efficiency.
Intel® Intelligent Power Capability. Turning off portions of the processor when they aren't being used improves overall energy efficiency and reduces heat production, resulting in a quieter, more energy efficient system.
Intel® Smart Memory Access. Increasing available data bandwidth means more multitasking with less slowdown—run more demanding applications simultaneously and accomplish more in less time.
Intel® Advanced Smart Cache. Placing data closer to the processing cores improves platform responsiveness and performance with a wide range of applications.
Intel® Advanced Digital Media Boost. Accelerates performance with a wide range of applications, including video, gaming, speech and image, photo processing, encryption, financial, engineering and scientific applications.
Intel® HD Boost. Available only on the latest 45nm Intel processors, this revolutionary technology takes Intel® Advanced Digital Media Boost and improves it even further enabling significant gains on the latest SSE4 instruction set. SSE4-optimized applications, such as video editing and encoding in high-definition resolution, will see additional performance improvements
Multimedia With professional-grade photo, music and HD video editing software readily available for consumers, it's becoming increasingly popular to create, edit, and share entertainment with friends and family. Unfortunately, these same applications are notoriously resource hungry. Built to handle the most demanding software, the four cores of the 45nm Intel Core 2 Quad processor help ensure that when you're working with high-resolution photos, exporting your next audio mashup, or editing HD-quality home movies, your computing platform will be able to keep pace with your creative muse.
Multitasking A computing platform featuring a new 45nm Intel Core 2 Quad-Core processor maximizes processing efficiency, allowing computer users to juggle multiple projects in multiple applications without experiencing the slowdown typically seen with traditional single-core processors.
Gaming Next-generation gaming is more than just pretty environments and smooth motion. Behind the incredible visual realism of waterfalls or the unlucky ricochet of a bullet are intense, high-speed calculations of asset streaming, terrain generation, 3D rendering, and physics effects. When running select next-generation games, each of the cores in the Intel Core 2 Quad processor can be dedicated to each of these individual processes, resulting in smoother, more lifelike graphics and further blurring the line between virtual and reality.
Customer Reviews

Last upgrade for 775 motherboard
E6750 to Q9550, great improvement for most of the games, none for others. Worth the shot if you already have a very good GPU.

Great processor fast shipping
I was quite impressed that this was shipped so quickly. The Q9550 is a an excellent fast quad, I've had no problems at all with the system I built and OC'd to 3.06.

Great Processor
I gotta say this is a great processor. I have an MSI X48C Platinum board with 4 gigs of DDR2 memory, ATI 4870 video card. I switched to 8 gigs of DDR3 here not to long ago and let me tell you my pc rocks. I could have went with the Intel I series of processors but after running this processoer I just can't see why i would. The price was right. I can play ANY game with no stutter and it's great for everyday and intensive applications. The new I core chips are prolly faster but really when you look at price vs speed... you can't go wrong if you go with this processor.

Great CPU
Last one for my 775 mobo... but this is definitely a keeper! OC is a dream!