Ubuntu Installation :: Using SD Card As Substitute For Hard Drive Safe?

Have you ever used an SD card as a substitute for a hard drive? The target machine is an MSI "nettop," more or less equivalent to a couple of netbooks glued together. It has dual Atom CPUs, 2 GB RAM, an optical drive, and a bunch of other ports and connectors not usually found on netbooks but standard on a desktop machine (thus the "nettop" moniker). So this is no powerhouse computer, but Ubuntu should run decently on it.

That's the thing: the machine has no hard drive. Instead, it has an 8 GB SDHC card. While the card is a "Class 10," and therefore well above average for an SD card, it's proving to be a poor substitute for a real hard drive. I'm working on the machine for a friend, and I think I'm going to have to recommend he spring for a new SATA HDD. Installing Ubuntu 10.04 from a CD-ROM to the SDHC card took forever. At least there was ample space (just try cramming Windows 7 into 8 GB!).

Similarly, the first round of updates took almost all day to install. The system is very sluggish in general, more so than is normal for a netbook-class machine, based on my experience with Ubuntu 10.04 on an Acer Aspire One D150. I suspect that the basic problem is the glacial speed of the SDHC card compared to a SATA hard drive. Although the SDHC card is rated for 20 MB/s reads, that's nowhere near even a slow SATA hard disk.

Write speed is likely a lot slower even than that, which perhaps explains the hours and hours required to install Ubuntu + updates. It seems as if launching apps is slow as well - again, probably a symptom of the SDHC card's sluggish reads, compared to a SATA HDD. Are there any secret tricks to make running Ubuntu off an SDHC card more bearable? Or should I just tell my friend he needs to buy a regular HDD?