Interesting I hadn't seen the HX450, it's new I think, the spec page is wrong for it, it should read:
•Supports the latest ATX12V v2.2 standard and is backwards compatible with ATX12V 2.01 systems.
•Ultra-quiet 120mm double ball-bearing fan delivers excellent airflow at an exceptionally low noise level by varying the RPM in response to temperature.
•Double-forward switching circuitry design offers maximum efficiency, up to 85% under wide load range.
•99% Active Power Factor Correction provides clean and reliable power to your system.
•Universal AC input 90~264V automatically scans and detects the correct voltage. No more hassle of flipping that tiny red switch!
•Dedicated single +12V rail offers maximum compatibility with latest components.
•Over Current/Voltage/Power Protection, Under Voltage Protection, and Short Circuit Protection provide maximum safety to your critical system components.
•High quality Japanese capacitors provide uncompromised performance and reliability.
•Auto switching circuitry provides universal AC input 90-264V
•Standard ATX PS/2 size: 5.9"(W) x 3.4"(H) X 5.9"(L); 150mm(W) x 86mm(H) x 150mm(L)
•MTBF: 100,000 Hours
•Safety Approvals: UL, CUL, CE, CB, FCC Class B, TÜV, CCC, C-tick.
Note the efficiency is upto 85% not upto 80%, I think the product spec page is taken from the HX520/HX620 which are seasonic not Channel well tech.
If it's another Channel well like the HX750 and HX850 it will be a seriously stable PSU.