Correct - depending on what patch you are running (the public releases do not have the patches yet for most hardware). There is still testing ongoing (primarily by Linux core devs), but it looks like 30% is the performance degradation cap. Some CPU tasks take a smaller hit.

A permanent fix (circumventing KAISER) will have to be integrated into the next generation of hardware.

In the near future – in all likelihood, later this month – at least Windows and Linux will get security updates that change the way those operating systems manage memory on Intel processors.

The slowdown will depend on many factors, but one report suggests that database servers running on affected hardware might suffer an average performance hit around 20%.

There are some great NYT security analysts covering the story, that you may be interested in following on Twitter.