That's not how CD ripping works unfortunately, especially when secure ripping is enabled. A CD can only be read so fast (determined by the maximum speed of the CD/DVD/BD drive) and if secure ripping is enabled each track is read/ripped multiple times and compared to ensure the the ripped data is exactly the same. That speed can then be limited to the minimum, especially if a CD you're trying to rip has a lot of scratches, is dirty, etc. Trying to multi-thread this process (there's no benefit for CD ripping from having more cores and memory), in my mind, wouldn't make any difference at all and would be pointless.
You can disable secure ripping and the ripping speed should increase, but do know if you do this there's no guarantee the data ripped is 1:1 of the original data on the disc. Like if a disc is scratched and you rip it without secure ripping you'll potentially hear skips and hiccups in the ripped track.
