I have a similar issue with my PS3. Thought it was the AV amp to start with. I don’t think it’s anything to do with HDMI leads, but to do with the PS3 overheating possibly. Our TV cabinet contains the PS3 and there is plenty of room around it, but it had a door in front of it. I now keep the door open when I’m playing on the PS3 or playing a DVD/BD and don’t seem to be encountering the same sort of issues (touch wood).
Maybe worth checking there is enough natural air flow around the PS3.
Mine is the new(ish) slim one btw.
edit. It did seem to be intermittent, so when you tried it with different leads, it could have just been luck.