Windows 98 serious lags

[Burinis]

I haven't used VirtualBox in a while. I decided to install the new version 7.2.6, and on top of it, I installed Windows 98SE with the SoftGPU driver and ICH AC97 audio (a Realtek driver). But here's what happened: Now Windows 98SE is freezing more often after loading the desktop, and the sound has become significantly choppy!
Windows DirectSound Audio Driver
ICH AC97 Audio Controller
Regarding the sound, only resetting the sampling rate to a low (default) value helps. But as soon as I restart Windows, the sampling rate resets back to high.
How can I fix this?

[Burinis]

Thanks everyone! I recreated the virtual machine using your old guide, and the sound stopped lagging.