Will a hybrid hard drive improve Visual Studio compilation times?

Question

I've seen various suggestions that hard disk speed is a big factor in Visual Studio compilation performance.

There is now a relatively cheap hybrid hard drive available called the Seagate Momentus XT.

This has a 7200 RPM hard disk of 250, 320 or 500GB and a 4GB SLC NAND SSD.

Has anyone tried this in their development machine? Did it improve performance? What kind of factor improvement was there?

Or is it the case that the hybrid hard drive cannot optimise typical compilation hard drive usage, i.e. performance is no better than a standard hard drive?

Answer 1

Hard disk speed is a large factor when initially loading the project, but for every compilation run after that, a machine with sufficient RAM doesn't need to touch the hard disk at all - all your source files will be cached by the OS.

Copying libraries and temporary files (.obj) around may still be problematic, but SSDs don't help with small file writes that much. Moving the obj/ directory to a RAM disk can be more efficient (without having to buy new hardware) if I/O really is a problem - but it usually isn't.

Check your CPU usage during compilation. If it's close to 100%, an SSD or hybrid disk won't help you at all, you simply need a faster CPU.

Answer 2

I think this article describes the SSD performace in relation to compilation times you're asking about.

Answer 3

I'd only consider doing this after you've already got enough ram in your machine. Consider putting your target files and temp files on a ram disc if the write IO causes a problem (which it should not if you've got enough ram).

I'm guessing it's cheaper and probably less disruptive (they don't need to move everything to a new HD) to buy your team an extra 8G of ram each for their workstation and get ramdiscs configured.