Don't get tricked by some software that claims to support lower speeds than supported by hard- and firmware combination.
I just tried myself. Used a Benq DW-1650 and a Plasmon CD-R. CD Speed shows a minimum speed of 12x (reported by the firmware). Selecting 1x speed in Windows burning app caused an error message. Ok, then let's go 4x. After ages of compiling the burn image (or whatever Windows does to prepare the burn), the plain burn time took about 6 minutes (I used my watch for "measurement").
Doing some math: 700MB data / 360 sec = 1,9 MB/sec. That's 12x.
Windows burn tool started with "estimated time: 20 min", which would have been correct for a 4x burn.
So even if a software offers ridiculously low speeds like 1x, this will not override the hard- and firmware limitations. Only exception I can imagine: The application is able to submit custom commands that are specific for a certain drive. But such is unlikely for burning applications which are targeted to end users.
But as your software already allows you to select 1x I think that 6x will be as low as that drive will go.
A good writer (a Samsung SH-S202/203 for example) can write CD-Rs with very low BLER & jitter at 16x, or even as high as 32x.
Exactly. I am btw starting to love my DVR-112 more than my 203B for its CD quality