The practical differences between various core logic platforms, which we commonly call chipsets, are few as long as you don't have special requirements. If you want to get a new system for office applications, to browse the Web, to communicate over the Internet and to play video, you can literally buy almost any PC, even the cheapest PC you can find. The higher your hardware knowledge or the more specific your application requirements are, however, the more attention you will want to pay to platform key features.
What you want today is a decent dual core processor, such as AMD's Athlon 64 X2 or Intel's Core 2 Duo, at least 1 GB of main memory, and a speedy 7,200 RPM hard drive with 200 GB or higher capacity. This will suffice to take on almost any consumer-type, multimedia or office application. This article deals with technology for Intel's Core 2 Duo processors on Socket 775, because they currently offer the best bang for the buck, which means that these processors offer the highest performance while consuming little energy at work. Stay away from single core processors such as the Athlon 64 or Pentium 4 unless you are on a tight budget. Dual cores don't necessarily increase performance - you need modern, thread-optimized software to do so - but they noticeably improve system responsiveness.
The most popular platform requirement is the ability to process 3D graphics; when it comes to gaming you should pay close attention to a PC's graphics subsystem. If you read about shared memory when looking at a system, this means that there is no dedicated graphics card installed. Instead, the motherboard core logic comes with simple built-in graphics support, which occupies parts of the main memory to store graphics data. This is very efficient, but inadequate for gaming or any type of 3D applications.
Buzzwords such as HyperMemory or TurboCache are indicators of ATI's or Nvidia's entry-level graphics solutions, which are somewhat better performers, but still don't provide enough 3D performance for serious gaming. Look for a current ATI Radeon X1600+ or Nvidia GeForce 7600+ graphics solution with 256+ MB of video memory to be able to game adequately. Generally speaking, the higher the model number, the better the 3D graphics product. We recommend reading our regular coverage in the graphics section for details.
Other platform features to watch for include the type and number of interfaces (PCI Express, PCI, USB 2.0), integrated hardware add-ons (networking, audio, storage or Firewire controllers) and an increasing variety of soft features for overclocking, monitoring, automatic hardware configuration or host-based RAID.
Finally, you may need to choose between a branded system and a so-called "no name". From a technical point of view, the two products may be very similar - the differences can always be found in terms of after-sales support. What does the vendor's support look like? What is the warranty period? Can you find technical information and software updates on the company's website? Can you get tech support on the phone? Consider these things carefully if you don't want to be your own troubleshooter.