It looks like Vista users that have noticed a slowdown in network traffic while they were playing music weren't imagining things, as Windows expert Mark Russinovich has reportedly confirmed that such a bug does indeed exist. According to PC World, the problem is confined to systems with multiple network interfaces (like both wired and wireless connections), and is only noticeable on a high-speed local network, not when you're on the Internet. Apparently, the bug lies in Vista's NDIS throttling code, which magnifies throttling in cases of multiple NICs, resulting in a slowdown in network traffic. In real word tests, Russinovich says he found that resulted in a 6 percent throughput on a 1Gb network with Windows Media Player playing, as opposed to a 20 percent throughput without it running. No word on a fix just yet but, as PC World points out, you may want to halt the tunes if you're planning on doing a lot of copying.