With my current batch of YUDEN000/T02 discs, my drive's firmware offers 8x, 6x & 4x. I choose 4x.
With a previous batch of RICOHJPN/R01, the same firmware version offered 4x & 2x. For those discs I chose 2.
The first discs I ever bought were CMC_MAG/R01. Firmware offered 2x & 1x, so I chose 1x.
My (employer's) laptop has a DVD burner, although I don't use it for burning since it doesn't support book-type bitsetting.
Its firmware offers 8x, 6x, 4x & 2.4x for the same YUDEN000/T02 media.