Hi there, Recently upgraded Mac (macbook aluminium 2008) with - 2 x 4gb sticks of Corsair 1067 ram. Was running lion and had loads of lock ups when watching video. Decided to downgrade to snow leopard as read online there are issues with video on lion. Anyway, now on snow leopard and whilst watching video is ok, i'm still getting random lock ups (have to power down as keyboard and everything has locked up). Should I go for a different set of RAM? All RAM tests I've run using memtest have come through ok. Don't think heat is an issue as the bottom of the case is quite cool to touch (only froze about 10 minutes ago). Any ideas greatly appreciated.