What would speed things up would be to have sensitive fields encrypted using the Advanced Encryption Standard (AES) on a system with an AES-Instruction-Set-(IS)-capable CPU, preferably with 256-bit keys, preferably in Ciper-Block Chaining (CBC) mode or, at least, Electronic Codebook Mode (ECB) with a salt - this can be done by simply prepending at least 1 character / byte to the data to be encrypted.
What would be even more secure would be to encrypt everything except /boot with AES in Extended Schedule with Ciphertext Stealing (XTS) mode in addition so sensitive fields in the database. You can use TrueCrypt to encrypt an entire disk, partition, or simply a TrueCrypt container in this manner - however, I would recommend system encryption so that no one can see the PHP (?) code containing the encryption key if your disk(s) get(s) stolen.
A known-plaintext brute-force attack on an AES key for data encrypted in ECB mode on a Cray XE6 with 1 million Opteron 6200-series chips would take at most 1.34188978904574248034587874518e+71 years just for the AES-NI instructions. Doing it on a Cray XK6 would place it at somewhere around 1.34e+69 years at most. This is, however, merely a brute-force attack, without breaking AES. Partially breaking AES would speed it up exponentially.
The most important thing is to use a complex pass phrase. This means that it has to be either a long string of a small set of characters (e.g. the letters of the English alphabet) or a short string of, basically, random bits whose byte value is not zero (null-terminator). Using an up-to-8-characters-long pass phrase consisting of the letters of the English alphabet places a brute-force attack on data encrypted with AES at below 10 seconds on a Cray XE6 with 1 million Opteron 6200-series chips and below 100 miliseconds on a Cray XK6. See Non-dictionary known-plaintext brute force attack on AES-256.
Even more secure would be to use something other than AES with a hardware accelerator, because AES acceleration is widely available. Even more secure would be to use both.