Are you still partying like it's 1999 on a 32-bit browser? Pshaw! To borrow a line for Weird Al Yankovic, "What kinda chip you got in there, a Dorito?" Well, Google is having none of it. Users running Chrome on a 64-bit Windows system with at least 4GB of RAM installed will be migrated from 32-bit to 64-bit, so long as they have Chrome configured to automatically update itself.
The migration will take place with Chrome 58, which Google has already started to dole out. if a user wants to go back to using the 32-bit build for any reason, it will still be available to download (manually). However, Google says the migration to 64-bit is intended to improve stability, performance, and security, so it's really not advisable to downgrade unless there is a specific reason, such as a compatibility issue.
Most users will find that migrating to 64-bit Chrome really presents no downside, just a handful of benefits. The biggest one is security. When Google first introduced 64-bit Chrome to its Stable channel in 2014, the company noted that it is able to "far more effectively defend against vulnerabilities that rely on controlling the memory layout of objects," to name just one of the security benefits.
There are upsides to performance, too.
"For example, the VP9 codec that’s used in high definition YouTube videos shows a 15 percent improvement in decoding performance. Stability measurements from people opted into our Canary, Dev and Beta 64-bit channels confirm that 64-bit rendering engines are almost twice as stable as 32-bit engines when handling typical web content," Google noted at the time.
To see which version of Chrome you're running (and to prompt an update), click on the three vertical dots in the upper-right corner and select Help > About Google Chrome.
Looking ahead to Chrome 59, macOS users will finally get their wish to have macOS notifications integrated with Chrome notifications.