Not true. It turns out that Speculative evaluation has side-effects, it changes the contents of the cache. This is the big issue. The contents of the cache are

Not true. It turns out that Speculative evaluation has side-effects, it changes the contents of the cache. This is the big issue. The contents of the cache are then detectable with timing attacks (the Spectre variants, but perhaps more will be discovered). Meltdown combines this flaw with Intel's own "surprising design" of speculative evaluation, which omits security checks and pulls kernel memory into the cache.