When the over 1 million people downloaded OS X Lion on launch day, few expected it to be Apple’s Vista (if you don’t get the joke, let’s just say that few expected it to run extremely slowly, much like Windows Vista did.) But a few users have been reporting a ton of Random Access Memory (RAM) being eaten up by a Safari process called “Safari Web Content.” This may be a bug for the new operating system, as according to TUAW, sometimes it can use up an entire gigabyte of RAM, with almost no tabs open in Safari. Obviously, with that much RAM being used by one process, the entire system would be extremely slow.

Here’s more from the original source:

Safari Web Content is a sandboxed subprocess of Safari that runs all webpage rendering. If you’ve got several dozen tabs open at once, it might make sense for the subprocess to use up that much RAM; however, I was seeing huge amounts of RAM usage even with only three or four tabs open. Four webpages shouldn’t be consuming over a gigabyte of RAM. Many people’s knee-jerk reaction has been to blame Flash for the excessive memory consumption, but that’s not the case here; Flash runs as its own separate process and has nothing to do with the “Safari Web Content” process or its runaway RAM usage.

The culprit is either OS X Lion or the new Safari update released a week ago. Hopefully Apple will fix this in the expected-to-be-coming-soon 10.7.1 update.