High CPU usage - Winamp skips a lot (since SP3 installed)

[ulillillia]

Ever since Microsoft released Service Pack 3, Winamp, even with realtime priority (the highest possible), any time there's high CPU usage, Winamp skips a bunch. By skipping, I mean it stops suddenly for around 20 ms causing ticks and other things to occur. Before SP3, this never happened, even with "high" priority. I've tried increasing the prebuffer to 1250 ms instead of 750. I'm using uncompressed WAV files (of 16-bit, mono for the format, sample rate is otherwise random from 30,000 to up to 140,000 Hz for the most part). WAV files are not CPU demanding at all, far less than MP3. Is there any idea what is causing this skipping? In case you're wondering, I'm using lame to convert WAV files to MP3's through 5 BAT files, the task that is using up the CPU. It also happens with virus/spyware scans, again, not causing problems until SP3. Do you know how to fix it so that Winamp doesn't skip as much, if it's possible? I get about 3-8 skips per second, 5 on average.