NEC3540a 48x cd-r burning failed?

I currently have a nec3540a with the original firmware (1.01) and the media I’m using is 52x memorex cd-r. I’ve been trying to use nero to make a data cd however, burning at 48x and 40x resulted in nothing but making extra cd coasters. I’ve been able to burn at 48x in the past with no modifications to my settings so I’m not sure what’s wrong. I was able to successfully burn at 16x though.
I’m not sure if this is relevant, but the data I’m burning is located on a slave drive.
I’m just wondering if there’s any suggestions that can help increase the burn speed, like what type of firmware I should update to, or a different brand of media.

Welcome to CD Freaks.

Dump those Memorex disks & get Verbatim.

Most here recommend 24x for data discs & 16x for Audio CDs but get some decvent media first.

Upgrading your firmware to the latest official NEC version would make a lot of sense.