Media on SD Card? or USB 3 Flash?

[bartersound]

I have an older MBP that has a 5200rpm hard drive.  My budget is such that I am unable to afford to upgrade it with a SSD for speedier playback.  My question is, what kind of results would I expect to see if I placed my media on an SD Card and use the MBPs built in SD slot?  Would this be just as fast as an SSD?  Faster than using the internal disks?  What about a USB 3 flash drive?

Many thanks!

[Reinhard]

SD card:

https://support.apple.com/en-is/HT204384

Older MBP do not have an USB 3 port.

Here is a very budget friendly solution:

http://troikatronix.com/troikatronixforum/discussion/1507/don-t-have-an-ssd-create-a-ram-disk-with-your-extra-ram

best

r