Core i5-2450M has been a highly successful notebook processor for Intel during the 2011 and the first half of 2012. There are still a lot of notebooks that come with this processor.
The Core i5-3210M is the newer processor that brings with it, among other improvements a better Integrated Graphics. This belongs to the Intel's newest Ivy Bridge series of processors - while the Core i5-2450M belongs to the earlier Sandy Bridge processor. Let us understand the difference between them with the help of the question and answers.
Question - So which of these two processors is faster from CPU perspective.
Answer - The newer Ivy Bridge Core i5-3210M is no doubt faster. From CPU perspective you will see slight gain in perfpormance when running CPU load heavy processes.
Question - What are clock frequencies of these two processors ?
Answer - Both are clocked identically at 2.50 GHz. Both have two cores and 4 Hyperthreads.
Question - How does a faster processor affect me ?
Answer - It should not make difference in daily computing. In reality you should see no perceptible difference for processes that takes less than few seconds to complete.
Question - How about the Graphics ?
Answer - The Ivy Bridge's HD Graphics 4000 ( the name of the integrated graphics in the i5-3210M) makes a huge difference. It is 50% faster than the Sandy Bridge HD Graphics 3000 in the i5-2450M.
Question - How does improved graphics benefit me.
Answer - It will not affect you in normal tasks. But if you are opening multiple videos and switch between these windows the better graphics makes it a bit zippy. The main difference will be in fast moving games where you will find Ivy Bridge giving better frame per seconds reducing stuttering.