UPDATE #1 - Jan 4th '17: AMD and ARM chips are also susceptible to this.
Now here's something that will not be fun to read about and that is that Intel's CPUs over the last decade (maybe more) have a design flaw that could allow malicious programs and scripts to read parts of a machine's memory that should not be able to. Thankfully, there is a patch in progress for Windows, Linux and Mac systems but the way the patch will work could result in a slowdown compared to before, of between 5 and 30 percent! That's not an all round drop and certain tasks will be affected more than others.
It's going to be mostly affected by high-level users such as gamers, along with cloud and web hosting companies who have literally thousands upon thousands of server racks packed with clients who they will now need to possibly move about because of the performance hit that will be felt.
AMD are apparently unaffected by this flaw however The first patches from vendors might go the easy route and stop the issue for everything before fine tuning it to only be active for those that are susceptible.
It's a major screw up and one that will be felt all over. Intel's stock price is already dropping.
Major flaw in millions of Intel chips revealed - BBC News
What's behind the Intel design flaw forcing numerous patches? | Ars Technica