I updated my old Gateway GT5040 desktop over Christmas.  New 1TB hard drive and Windows 7 Professional 64-bit.  Everything went great.  Even my Hauppauge PVR-150 was recognized!  Sound is great.  Performance is very good.

Then I noticed my spiffy new 64 bit OS was not utilizing all of the memory on my system (Found: 4GB, Utilizing: 3.25 GB)  A couple of quick searches turned up some good leads, but I had no luck getting the machine to use the entire 4 GB.  I began looking around for hardware information.  My motherboard is an Intel Cortez, D945GCZ.  A quick read of the manual pointed out the MB would only use about 3.25 GB of RAM, with the rest mapped to peripherals above 3 GB.

To make a long story short: I am happy with Windows 7, but my old hardware is somewhat of a problem.  I will just live with 3.25 GB of usable memory.  At least my hard drive speed is really smokin' and it's a respectable development box.