I installed Windows 7 64-bit on my desktop and was forced to overcome a few problems. It took a great deal of searching to find the solutions, so I’m detailing it here to help others. My hardware is an ASUS P5B motherboard with an Intel Core2 Duo 6420. The first lesson is never use the Windows tools to upgrade the BIOS. I did and it screwed up my BIOS. I had to send for a replacement motherboard from ASUS (they responded quickly and without any hassles).
The first problem was that I added 4GB RAM for a total of 6GB, but only 5GB showed up in Windows. The solution here is to turn on the “Memory Remap Feature” under Advanced->North Bridge Configuration in the BIOS. See here for an excellent walk through.
The second problem was my new 1TB external eSATA drive wouldn’t show up in Windows. It turns out you need to turn on AHCI in the BIOS. However, if you’ve already installed Windows 7 then you need to reinstall the OS with the feature turned on. Thankfully, this post explains how to do it without reinstalling the OS. In the BIOS, you need to turn on SATA in the BIOS under Main->IDE Configuration->Configure SATA As… and choose AHCI. Also, under Power->ACPI 2.0 Support I switched that to Enabled. Don’t know if that last bit helped.
The final problem was that the eSATA drive showed up perfectly when I booted; however, it would disappear when I resume from sleep mode. I fixed this by installing the latest JMicron RAID drivers from ASUS. Others suggested installing Intel’s Matrix Storage drivers, but the installer complained that I didn’t meet the software requirements, whatever that means.
Also, on my machine the eSATA interface is almost 2-3X faster than USB. Using HDTune to measure the transfer rate, eSATA was minimum of 40MB/sec, maximum of 90MB/sec and average of 72MB/sec. With USB it was 33MB/sec min, max and average. Therefore, if you care about speed then eSATA is more important than the quality of the disk itself.