If you have an SSD, I suggest placing the folder of small files on it. As SSDs are designed to handle small transfers of many 10,000 x 4KB IOPS per second, the SSD will get around the read bottleneck. Alternatively, if you have plenty of RAM, you can try creating a RAMDrive to store the folders of small files on, e.g. a 1GB RAMDrive if you’ve under 1GB of small files to write.
If you’re using ImgBurn, you could try increasing the buffer size. It’s 80MB by default, but can be increased to 1024MB. Go into the Tools menu, select ‘Settings’, then the ‘I/O’ tab, ‘Page 2’ tab below and drag the ‘Buffer size’ to the end. The side effect is that it will take longer to begin writing as ImgBurn will first read 1GB of data into memory before it starts burning the disc. However, when it reaches the small files, the 1GB will give 1 to 2 minutes of burn time (with DVD) as it fetches the small files. Even if the buffer runs out, this will reduce the number of start/stop cycles.
One other possibility is anti-virus protection slowing down the read times, especially if your saved webpages contain a lot of JavaScript files. If you find that the buffer keeps running down even with using an SSD or RAMDrive to hold the small files, try disabling your anti-virus realtime protection for the duration of the write process.