New PSU in a HP Case

Jaxem

Honorable
It's a normal size case and the Corsair will be the same size as the one you pull out, PSU's are standardized like most PC components, in this case both PSU's are ATX and it shouldn't change airflow much if at all. With an OEM case, i doubt you even have more than just a CPU fan and maybe an exhaust if you're lucky. They're about being quiet, not performance.