What's the difference between the timings of these two RAM? What does the 24 in the Corsair RAM mean?
There are typically four timings used to describe a RAM's speed, however the 4th one is not always reported (like in the case of the first RAM you list). The most commonly referred to speed is the first number listed: the CAS Latency.
As to your specific question - it looks like the first 3 timings are identical. The 4th one we can't compare because we don't have the information. You can take a look at this Wikipedia
posting - it's semi-technical but hopefully it will provide you with basic understanding.
Rule of thumb: lower is better.
Hope this helps.