The Sorcerer
oh wow...Xenforo!!!
You should not do any testing/stress-testing with a substandard psu in the first place. Even if you change the psu, chances are that this psu might have damaged something (or it is a DOA- can't say without diagnosing which hence leads to the first sentence of this comment) so do the needful and switch to either 2 of the ones recommended above and then we'll continue with the troubleshooting steps.