I am going to do a reinstall of Ubuntu on my Laptop this holiday. I have an ASUS UL30VT, with no flash drive, and i just wondered. I never use my card-reader for anything, but i have a 32GB SD-card that i do not use really. I was then wondering if installing Ubuntu on that SD-card will improve my performance much? Would it be like SSD
By experience, I can tell you that running Ubuntu on a SD card is usually unbearably slow. You won't get anywhere near SSD-like performance. This is due to the read and write speed limitations of SD cards and card readers.
Installing on a USB flash drive would give you at least equal, and most likely significantly better, performance.
Please note that I am only speaking from personal experience.
Worth noting that there's SD cards now that have R/W speeds of up 260MB/240MB per sec, respectively: See this article
I have done this and the result wasn't pleasant(read: it was slow). The instructions I followed were: