I know that symmetric cryptography is faster than asymmetric, but on average how much faster would it be if you were encrypting and decrypting a 2MB file?
The page https://www.cryptopp.com/benchmarks.html has a comparison of the speeds of a number of different algorithms. You will have to do a little math to covert to the time necessary to encrypt a 2MB file, but this should give you the base information necessary.
In general case, symmetric cryptography is not faster that asymmetric ones. For example with this asymmetric cryptosystem we are able to encrypt more than $40Gb$ per second. This huge number is not comparable with slow systems such as $1024$-bit RSA that is $40Kb$. It is attractive that throughput of encryption with AES-$128$ is less than $5Gb$ per second(according to the mentioned paper).