South Bridge deals with this, if you haven't a fan on that it would probably help.
North Bridge deals with CPU, RAM, etc.
Either of the cards above would work, but you need to make sure the power supply you give to the external drive is a clean source. I.e. if you're not using a caddy with a clean supply, then come off of the internal PSU and use an extender rather than try and use a power adaptor.
South Bridge deals with this, if you haven't a fan on that it would probably help.
North Bridge deals with CPU, RAM, etc.
Either of the cards above would work, but you need to make sure the power supply you give to the external drive is a clean source. I.e. if you're not using a caddy with a clean supply, then come off of the internal PSU and use an extender rather than try and use a power adaptor.