Ripjaws series RAM differences?

[Blueprint]

I'm building a rig with an AMD Phenom II X4 965 on an ASUS M4A79XTD mobo (at least that's the best bang for the buck I could match it up with). The mobo says it does DDR31800 (O.C.) with standard support for 1600. So my question comes in selecting the RAM. I came across two version of G.Skill Ripjaws memory:

Both were 2 GB sticks that were DDR3 1600 (PC3 12800). The differences were in the Cas latency, voltage, and timing. I'm not well versed in these things so I was hoping for some assistance. Here are the specs:

Cas Latency: 9, Voltage: 1.5v, Timing: 9-9-9-24-2N vs.
Cas Latency: 7, Voltage: 1.65v, Timing: 7-8-7-24-2N

I plan on using the computer mostly for encoding video and acting as a media server. My basic understanding is that lower numbers = quicker operation. Am I missing something else?

 

[GarfieldtheCat]

I'm building a rig with an AMD Phenom II X4 965 on an ASUS M4A79XTD mobo (at least that's the best bang for the buck I could match it up with). The mobo says it does DDR31800 (O.C.) with standard support for 1600. So my question comes in selecting the RAM. I came across two version of G.Skill Ripjaws memory:

Both were 2 GB sticks that were DDR3 1600 (PC3 12800). The differences were in the Cas latency, voltage, and timing. I'm not well versed in these things so I was hoping for some assistance. Here are the specs:

Cas Latency: 9, Voltage: 1.5v, Timing: 9-9-9-24-2N vs.
Cas Latency: 7, Voltage: 1.65v, Timing: 7-8-7-24-2N

I plan on using the computer mostly for encoding video and acting as a media server. My basic understanding is that lower numbers = quicker operation. Am I missing something else?

For RAM timings, yes, lower numbers are better (faster). But the difference is usually less then 5%, and a lot of times only 1-2% for real world apps (as opposed to running specific memory benchmarks, or running superpi).

JEDEC standards are 1.5V for DDR3, so the 1.65V RAM is probably the same chips, just tested to run at the tighter timings, and thus requiring the higher voltage to be stable at those tighter timing.(like buying a pre-tested CPU for overclocking)

I would just go with the 1.5V RAM, it will run cooler, and probably be cheaper as well. If for some reason the 1.65V RAM is cheaper, get that and run it at "normal" settings and voltage. (Most motherboards will require to manually set the increased voltage and faster timing settings, so if you run your BIOS settings as "auto", most likely your RAM will run at 1.5V, 9-9-9 instead of the faster timings)