Memtest86

From Wiki

Memtest86 is an incredibly useful little program, however the actual obtaining of memtest isn't quite what I make it out to be.

wget http://www.memtest86.com/memtest86-3.2.tar.gz
tar zxfv memtest86-3.2.tar.gz
cd memtest86-3.2/
make
mv memtest.bin /srv/diskless/memtest86

Alternately, you can download it here, in gzip form. You need to decompress it with "gzip -d memtest86.gz", and then move it to your TFTP boot directory.

Thanks to Lantins@Freenode for this information.