Seasonic psu running hotter than expected

[Antonio Lambranca]

Hi. I'm the happy owner of a Seasonic PSU like the one below bought about a week ago.

https://www.overclockers.co.uk/seasonic-core-gold-gc-500-500w-80-gold-power-supply-ca-071-ss.html

However, I have noticed that the back and the top of the case (I still have an old pc case) are very warm. I have installed the psu fan down as by the instructions.
Also, the Seasonic PSU calculator did calculate a 370W power draw and recommended a 420W so it's definitely not due to running it too hard.
Now, should I be worried about it or is it normal?
Is there anything I can do to help it run cooler such as adding case fans? I am building a new pc soon so will get a new case.

Below are my pc specs:
Standard case with PSU on top and 1 exhaust case fan by the CPU.
AMD FX4300 with Artic Cooler
Gigabyte GA-970 DS3 ATX
20GB DDR3 1666Mhz
EVGA GTX 550Ti
Kingston SSD 120GB
Seagate Barracuda 1TB
LG DVD-RW

 

[Antonio Lambranca]

Thank you everyone for your input.
Following your advice I did some cable management and installed an intake fan by the CPU (it's the same but this time is intake not exhaust).
I am going to order 2 more fans to pull in more cool air and will try to get a used m-atx mobo so I can buy the new case.
Here's the tidied up case now.
Messy case.

Tidy case