Try setting your Power Management to spin down your HD after 3 or 5 minutes and see if it has any important impact. If your trade execution and graphics are operating out of memory, spinning down will be just fine and will likely solve any heat and longevity problems. If your HD needs to spin up at a crucial time, you may not want to wait the 3 seconds or so required.
I have mine spin down after 3 minutes, and never notice until I start a new program or website.