When viewing the Store, Community, or User Profile tabs in the Steam Client, Steam displays the following message:
The Steam Web Browser requires a CPU that supports the SSE2 instruction set. Intel added support for SSE2 instructions in the Pentium 4 (c.2001), and AMD added these instructions in c. 2003 Opteron and Athlon 64 processors.
If your CPU or computer lacks the SSE2 system requirement, you will need to view Steam-related web content in your default web browser.
We recommend upgrading your computer with a CPU that has SSE2 support if you would like to use the Steam Client web browser.
32-bit Linux distributions are also no longer supported. Please install a 64-bit Linux distribution to make use of the Steam browser.