I have ASUS G53JW notebook with two HDDs (2x500GB Seagate ST95005620AS). Second HDD automatically stops after 30 seconds of inactivity. Always. I'm using Windows 7 x64. If I run a game from this HDD there are always lags when something is needed to load after 30 seconds of inactivity of the HDD. Standard power management settings do nothing with this HDD, though "auto shutdown after" property is set to "never".
How to fix it, anyway?
