useful hardware diagnostics to run

Question

I am wondering what would be some useful hardware diagnostics to run on a new machine (I got a refurbished Lenovo T420). So far I have done the following

• used sudo smartctl -a /dev/sda1 | grep -i -E 'hours|cycle|count' to check that my hard disk is not unreasonably old
• used memtester to test the memory (but can't use it to test the entire 8 gigs of RAM as the system becomes very unresponsive)
• checked for burnt pixels using videos that are available on youtube
• looked into the dmesg and /var/log/kern.log. I basically grepped for 'error', 'critical', 'alert' etc. but it's hard to decipher the output and I am not sure I am using the correct grep strings. Some errors were found (reported here) but the output is rather verbose and I am not sure I need to worry about them.

Am I missing / misunderstanding anything on the above and what might be some other Linux tools one might use to ascertain whether the hardware of a machine is in good shape?

Answer 1

For the memory test, rather than relying on the memtester application I created a live Ubuntu USB flash drive using UNetbootin and run a thorough memory test as described here.