How much influence the latency of the memory performance?

hi,
i want to know how much influence the latency of the memory performance? We know that the latency time is required between the clock turns to the ram receive new series of bits, then sends instructions to the CPU, and empty as those already used. (more or less correct).We also know that it is better than CL6 a CL5, but turning to the network are not able to find a test.Anyone have any idea?Any recommendations and suggestions are appreciated.

CL6 with the memories have a time to refresh active at 127ns, while CL5 have time to refresh at 105ns. So, as far as I know, the faster CL5 son in "empty" of data in memory.

The latencies affect more or less depending on the chip on the motherboard, because AMD has the memory controller integrated into the processor and the Intel chipset has not ... so you say or what influences or whether it is better to lower latency on Amd or Intel.
Also in shaping the new PC for use multitasking (3d games and nothing) I'm trying to figure out whether to choose the banks with high frequency (on the AM2 + Phenom allow up to 1066 mhz P8500) and then also with voltages (from 2.1 volts and above) and higher latencies (CL5) or even frequency of 667 MHz (PC5300), but lower latency (CL4 or CL3 on benches 1Gb) and voltages around 1,8-1,9 volt? In other words, for a multi-use applications with many less demanding in terms of RAM (compared to games), I have not yet understood as parameter between speed, latency (and voltage) should give priority.

I believe that ultimately stabilize at me from a 4 GB ... are sufficient for now.