HD of same size, same speed, but different cache's...performance difference would depend on what type of workload the drive is doing. But yeah, don't pay the big bucks for something that will make little to no difference with the tasks you are doing with the system.
This post is really dated. So what will cache do today and do I really need 64 cache for gaming? Can I drop to 32 or 16 cache? HDD prices are really expensive. I do want to take advantage of the ASUS P8Z68-V PRO/GEN3; any suggestions for a (gaming only) HDD?