Using Bootchart to monitor the boot process, we first boot Mandriva 2009.1 beta without Speedboot and then again with Speedboot. It took 27 seconds to boot normally and 37 seconds to boot with Speedboot. Yes, Bootchart actually reports it taking 10 seconds longer when using Mandriva's technology to speed the boot process, since more processes are deferred to after the display manager initialization.
Though if you look at the Bootchart results, you can see which tasks are starting up earlier under Speedboot. Under the normal boot process on the Atom netbook it took about 17 seconds until gnome-session was started, but under Speedboot the GNOME Session started in less than 8 seconds. With Speedboot, the X Server starts running within 5 seconds. What is also interesting to note is that the disk throughput dropped under Speedboot. When booting normally the SATA 2.0 SSD maxed out with 98MB/s reads where under Speedboot that peaked at 59MB/s. From the Bootchart graphs you can also see far less services were started under Speedboot.