Hi, I've got a really strange problem. In my Pc I've got 1 SSD and 2 x HDD's. Currently the 2 x HDD's are making a heartbeat pulsing sound, one is louder than the other so I thought it was dying and replaced it but the same problem occurred with the new drive. So I've investigated further and it seems the heartbeat pulsing only happens when both HDD's are plugged in. I've tried swapping power cables & SATA cables around but nothing seems to make a difference. My only conclusion is that it could possibly be a power issue but I realise HDD's use very low power and can't find anything about this online anywhere. Buying a new PSU would be a significant amount of cash if it's something else. Any ideas anyone?