I just gave in and bought a new machine JUST for testing. It is faster than my regular development machine at 3.2 ghz, is a P4 and comes with 1 gig of ram already. They just kept slapping all of these discounts on ($50 off on any Optiplex between $400-$500 and $50 any GX270 or SX280) and the whole thing was under $400, no tax, free shipping. Not too shabby. It is going to replace my current left over test box that is 700mhz and has 512 mb ram (and runs Whidbey Beta2 and SQL Server 2005 Developer perfectly fine thank you very much!!) It was definitely a satisfying purchase!
http://www.AcehAid.org
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