在具有MySQL与NoSQL的单个服务器上，Key-Value数据库是否存在高性能差异

In my PHP application I have a 470M rows table weighing 200GB in a MySQL MyISAM partitioned table on one server. Usage includes 70% Writes/30% Reads. I'm trying to improve performance. Main problem currently is read/write contentions due to table-level locks. I'm trying to decide between two options:In my PHP application I have a 470M rows table