Rather than minimizing the first browser screen, make it a half-screen window and open the 2nd browser copy in another half-screen window. Then you can sit there "reloading" the first screen and watching the high bid and the clock. When you decide to bid, hit the 'submit' button on the other browser copy which is already open and active.

One of the most useful features of Windows is the ability to run more than one copy of a program at the same time. Yet, I'll bet half the Windows user don't use it. Even less well known is the ability to run several WWW activities at the same time. When eBay gets slow and you're waiting for a response, leave it running and go check your email. When you're doing a download of an update to one of your programs, you can go checkout The Chip Board and it hardly slows the download at all. Your PC sorts out all the simultaneous packets flowing to and fro without losing a single one!