Long time for BIOS to load

Hi,

Since a few days, I'm having trouble with a 6 years old computer...

My computer :

MB : ASRock Z87 Pro4
CPU : i5-4670K
RAM : 2 x 4Go DDR3 Corsair Vengeance Pro PC3-12800 Cas 9
GPU : MSI GTX 760 Twing Froze OC GAMING 2Go
Alim : 520W Antec High Current Gamer Series
SSD 120Go for Windows & HDD 1To for data

I've been using this computer for 6 years now with no problem...

But now : The boot time (but more the BIOS loading time I think) is taking so much time... It can take 1+ min more to load (show the BIOS' logo)... And I've notice something strange... When you ask Windows to reboot the computer... It never shuts down and never reboot (or at least I've not waited long enough haha)


What I tried :

1. Clear CMOS


2. Boot with only 1 RAM (it never boots... page 19, I've tried on A1 and A2 : https://download.asrock.com/Manual/QIG/Z87%20Pro4_multiQIG.pdf)
   


3. Boot without USB Device (Doesn't change)


4. Crystal Disk Info : looks fine


5. Memtest : no errors


6. New windows installation : No change, but I knew it would not change haha


7. HOT CPU Tester Pro : no errors


8. AIDA64 : no errors

The only strange behaviour is with RAM, I tried using 2 DDR3 G.Skill Ares Bleu - 8 Go (2 x 4 Go) 1600 MHz - CAS 9 and the computer boots, shuts, boots, shuts and it never ends...

So for me it's either a motherboard problem or with the RAM.

What I don't understand is that every test did not show a RAM problem...

Any Idea ?

Thanks !