Macbook air 2012 strange freeze issues

[mcb2012]

Macbook air 2012 have some strange issues.

It freezes randomly (rarely completely) usually just some apps stop responding or very slow

tried reset src and nvram

when tried to run diagnostics (holding d on boot or hiding option d on boot) it went to internet recovery screen with spinning globe, asked to choose wifi, after I chose wifi - nothing happened.. waited for couple of hours.


No idea how to continue troubleshooting the issue.
Do know that battery is pretty old and weak (coconut battery reports 40-50% of original capacity)
Running high sierra with all updates

 

[Audit13]

Could it be a lack of ram or free drive space?

 

[mcb2012]

Could it be a lack of ram or free drive space?

freshly reinstalled , nothing installed , clean macOS (plenty of HDD space and ram seems to be ok)
it do work fine part of the time

 

[Audit13]

Check activity monitor for ram and cpu usage when using apps that cause the freeze or slowdown.

 

[mcb2012]

nothing there,

Check activity monitor for ram and cpu usage when using apps that cause the freeze or slowdown.

nothing there
I am looking for much more advanced troubleshooting steps

 

[Audit13]

Maybe take it to apple and have them run their own diagnostics? Could it be overheating?

Don't really have any more troubleshooting tips other than running software like entrecheck: https://etrecheck.com/