Apple states the following basic Snow Leopard system requirements are:

• Mac computer with an Intel processor (IA-32). "Yonah" processors such as Core Solo and Core Duo can run only 32-bit applications; later x86-64 architecture processors such as Core 2 Duo, Core i5 and i7 are also able to run 64-bit applications.
• Mac OS X 10.5.6 or later (10.5.8 is recommended)
• 1 GB of RAM
• 5 GB of free disk space
• DVD drive (also accessible via Remote Disc) or external USB or FireWire DVD drive for installation

Additional requirements to use certain features:

• QuickTime H.264 hardware acceleration support requires an Nvidia GeForce 9400M, 320M, or GT 330M graphics card.
• OpenCL requires a supported Nvidia or ATI graphics card.

Snow Leopard drops support for PowerPC-based Macs (e.g., Power Macs, PowerBooks, iBooks, iMacs (G4 and G5), all eMacs, plus pre-February 2006 Mac Minis and the Power Mac G4 Cube), although PowerPC applications are supported via Rosetta, which is now an optional install. In 2020, two developer previews of Snow Leopard that are universal appeared on the Internet that can be booted on select G4 and G5 Power Macs with modification and patching.

Mac OS X Snow Leopard is a release that refined the existing feature set, expanded the technological capabilities of the operating system, and improved application efficiency. Many of the changes involve how the system works in the background and are not intended to be seen by the user. For example, the Finder application was completely rewritten in the Cocoa application programming interface, from its previous Carbon codebase. Despite significant changes in the software, users will experience almost no changes in the user interface. Snow Leopard includes the following changes:

• Mac App Store – An app marketplace built in the image of the iOS App Store. Released in version 10.6.6.
• Boot Camp now allows Windows partitions to read and copy files from HFS+ partitions. The new version also adds support for advanced features on Cinema Displays and a new command-line version of the Startup Disk Control Panel.
• The Finder has been completely rewritten in Cocoa to take advantage of the new technologies introduced in Snow Leopard.
• A much smaller OS footprint, taking up about 7 GB less space than Mac OS X Leopard. Some of the recovered disk space (~250 MB) is because printer drivers are now downloaded or installed only as needed, rather than being pre-installed. The default install only contains those drivers needed for existing printers and a small subset of popular printers.
• iChat enhancements include greater resolution video chats in iChat Theater and lowered upload bandwidth requirements.
• Microsoft Exchange support is now integrated into the Mail, Address Book, and iCal applications. However, only Microsoft Exchange 2007 is supported and customers using prior versions of Exchange must either upgrade or use Microsoft Entourage.
• Full multi-touch trackpad support has been added to notebooks prior to those introduced in October 2008. While the original MacBook Air and other early multi-touch trackpad enabled notebooks had support for some gestures, they were unable to use four-finger gestures. This limitation has now been removed in Snow Leopard.
• Preview can infer the structure of a paragraph in a PDF document.
• QuickTime X (version 10), the next release of QuickTime player and multimedia framework, has been completely rewritten into a full 64-bit Cocoa application and builds on the media technologies in Mac OS X, such as Core Audio, Core Video, and Core Animation, to deliver playback. Apple has redesigned the QuickTime user interface to resemble the full-screen QuickTime view in prior versions, where the entire window displays the video. The titlebar and playback controls fade in and out as needed. QuickTime X also supports HTTP live streaming and takes advantage of ColorSync to provide high-quality color reproduction. If Snow Leopard is installed on a Mac with an nVidia GeForce 9400M, 320M or GT 330M graphics card, QuickTime X will be able to use its video-decoding capabilities to reduce CPU load.
• Safari 4 features Top Sites, Cover Flow, VoiceOver, expanded standards support, and built-in crash resistance, which prevents browser crashes caused by plug-ins by running them in separate processes. Safari 4 is bundled with Snow Leopard. Safari 4 is also available for free for Mac OS X Tiger, Leopard, and Windows.
• Time Machine connection establishment and backups are now much faster.
• VoiceOver has also been greatly enhanced in Snow Leopard. Reading of web pages is improved with Auto Web Spots — areas of a page automatically designated for quick access. On newer Apple portables, trackpad gestures can be used to control VoiceOver functions, including the "rotor" gesture first seen in VoiceOver for the iPhone 3GS, allowing for the changing of certain VoiceOver navigation options by rotating fingers on the trackpad. Braille Display support is also improved, with Bluetooth displays supported for the first time.

• AppleTalk, a network protocol suite that was introduced in 1985, is no longer supported. Apple Filing Protocol over TCP/IP is still supported in Snow Leopard.
• It is no longer possible to change an application's language using the Finder's "Get Info" dialogue. While there are workarounds for some applications, others (such as Adobe After Effects CS4) will not be able to be run in a different language than the one selected in the system without using Terminal commands or third-party software. The option to change language for individual apps was added back in macOS Catalina in 2019.
• Creator codes have had their priority in the application selection process reduced (Creator codes are per-file metadata attributes that define, for a file that has a creator code, what application should open that file, regardless of its extension).
• Creating or updating Hierarchical File System (HFS Plus predecessor) volumes is no longer supported.

While the Finder was completely rewritten in Cocoa, it did not receive a major user interface overhaul. Instead, the interface has been modified in several areas to promote ease of use. These changes include:

• The "traffic light" titlebar controls are now slightly lighter in appearance and have less depth than they did in Mac OS X 10.5.
• Exposé can now display windows for a single program by left clicking and holding its icon in the dock. Windows are arranged in a new grid pattern.
• Contextual menus which come out of Dock icons now have more options and have a new look, with a semi-transparent charcoal background and white text.
• An option has been added to the Finder preferences that allows the user to modify search behavior. The default setting can be selected to (1) search the entire computer, (2) search only the current folder from which the search was initiated, or (3) perform the search based on the previously used scope.
• Dock Stacks, when viewed as a grid, allow viewing of a subfolder as a new stack, rather than launching a Finder window, in a manner similar to "tunnelling". When viewed as grids or lists, scroll-bars are provided to navigate folders with more items than the current screen resolution will accommodate, as the program does not scale the icons to show as many as possible the way it did in OS X 10.5.
• The default gamma has been changed from 1.8 to 2.2 to better serve the color needs of digital content producers and consumers.
• Windows can now be minimized directly onto their application's icon in the dock.
• Faster PDF and JPEG icon refreshes.
• When searching for a network, the AirPort menu-bar icon animates until it finds a network and shows network strength of available networks in the drop down menu.
• Prefixes for bytes are now used in strictly decimal meaning (as opposed to their binary meaning) when describing disk space, such that an indicated file size of 1 MB corresponds to 1 million bytes, as commonly used by hard disk manufacturers.
• Snow Leopard shuts down and goes to sleep faster.
• New wallpapers
• As with most upgrades of Mac OS X, new wallpapers are available. There are new wallpapers in the Nature (two of which are of snow leopards), Plants and Black and White sub-folders under the Apple folder. Furthermore, there are new Apple wallpaper sub-folders with multiple wallpapers:
• Art: Dancer on the Stage, Nighthawks, Poppies Blooming, A Sunday Afternoon on the Island of La Grande Jatte, Suprematism, The Great Wave off Kanagawa, and Water Lilies.
• Patterns: Pinstripe and Saree.
• New solid colors can be used as wallpapers as well. There is a new blue and gray, as well as a solid kelp which serves as the "green wallpaper." The default "space nebula" wallpaper has been updated as well.