vangellis

Hi I want to upgrade my PC to 8 Gb of memory, it only has 2 memory slots avalable and a 4Gb memory module is installed in one of them. Now on the homepage of my motherboard, it states that it Supports two unbuffered DIMM of 1.5 Volt DDR3 800/1066/1333* (OC) DRAM, 8GB Max. Now I have no idea what the (OC) means although I think it's overclocked. So I want to purchase a 4Gb memory module but am a little unsure which one I need. I found these 2 but are they right or not. http://www.pcworld.co.uk/gbuk/desktop-memory-dimm/713_7308_70369_xx_BA00003090-BV00256015-BA00003091-BV00256020-BA00003094-BV00256035-BA00003093-BV00256031/xx-criteria.html http://www.pcworld.co.uk/gbuk/integral-pc3-10600-ddr3-pc-memory-4gb-dimm-ram-09993530-pdt.html I appreciate your help and advise Vangellis