Is it advisable to replace the internal HDD of an old Mac mini by a Solid State Drive? I have an old Mac mini 1.1 updated 2.1 (2.0Ghz CPU/4 GB RAM).

My problem:
Flash videos use all CPU resources and my Mac gets very hot. 

My question is: Is it advisable to buy a Solid State Drive and put it in and use it or is it time to sell my Mac mini?

Can someone please upload a video showing a working Mac mini with an SSD? How does Flash on it and an app stress test.
Since the decoding of Flash videos primarily stresses CPU and depending on the codec and the video card the GPU an SSD doesn't help much (assumed you have enough RAM).

Another caveat is the internal HD Interface of the Mac mini 1.1/2.1: Serial ATA (1.5 Gb/s) which roughly equals to a max. throughput of 150 MB/s. Modern SSDs provide up to 600 MB/s / 500 MB/s (read / write). As a consequence you will lose up to 2/3 of the possible bandwidth by attaching the SSD to your internal interface.

So better save the money and get a more recent Mac.