8 gb is more than adequate; I use it for my 32 gb ssd with hibernation disabled to maintain the maximum space available. Extra ram means the hardrive will have to use up more space to accomodate it.
Frequency depends on your motherboard chipset and bios adjustments. Intel recommends 1333 for it's 1155 cpus, but some new boards will default to 1600, which is slightly faster. Some folks will overclock their cpus which may increase the ram speed if it's capable; I don't recommend it, but some are lucky to find the sweet spot for their cpus and don't have any issues with it.