RAM Latency question

Is this DDR3 1600 with a cas latency of 7 better than this DDR3 2133 w/a cass latency of 9?

They are nearly equivalent, and are likely to be around a plus or minus 0% - 3% difference in the vast majority of applications. Theres a semi exception if you intend to build an AMD APU system while using the APU, in which case the memory acts like video memory, and will benefit more from higher Mhz. If you have a dedicated video card, then it wont matter. I would probably go with the 1600/7 over the 2133/9 under most circumstances. You'll be dual channeling it anyways, and you don't get as much out of a Mhz bump as you might think.

id be shocked of anyone could tell the difference between the two side by side

For Intel systems, every 266Mhz jump is about 2,5 latency in performance.

Also each RAM usually performs better in a certain latency and Mhz. Thats why sometimes you will see that even with faster Mhz and lower latency, RAM performs worse than before.

Since I have a 2133/CL11 RAM, I can provide also some everest numbers if you like to check them.

$175 for RAM? wow that's a lot.

Good 16GB kits aren't cheap.

I played around with RAM CAS a lot. Here is what I think...

First higher speed memory is good if your bandwidth starved. Which if your running integrated graphics or do a lot of multitasking. Then it makes a big difference.

CAS on the other hand makes things feel zippy. Though very tiny amount I did notice it. I down clocked my memory 7-7-7 @ 1333. It's stock setting is 9-9-9 @ 1866.

Here is memory I do a ton of builds with....

http://www.newegg.com/Product/Product.aspx?Item=N82E16820148657

I know it's expensive. But it's also got 4 things going for it... Size, latency, voltage and density.

A) You only pick high speed RAM if you're editing stuff, gaming wise it won't make any difference

B) If you have the option to take faster RAM speed at the same CAS latency without spending extra money on it - go for it.

C) You'll only benefit on some games with quad channel kit (which sadly only available on the 2011 and 2011-3 sockets)

For gaming, you want a lower cas latency, you don't need a lot of bandwidth. The 7-7-7 kit will be better.

DDR3 1600 = 800 MHz memclk = 1.25ns cycle time * 7 ( column access time ) = 8.75ns access latency

DDR3 2133 = 1066.667 MHz memclk = ~0.938ns cycle time * 9 ( CL ) = 8.43ns access latency

i doubt you'll see a meaningful difference in perf. w/ a 300ps difference. but at least the 2133 will also get you a bandwidth increase as well

I was thinking this RAM would do well with this heavy gaming build. Thoughts?

I used to use 1600mhz ddr3 ram on my current pc, later got some 2133mhz ram. I did a few game benchmarks on my 1600 before putting in my 2133 ram, the results were too close to determine what was better. I knew kinda before hand from benchmarks that it wouldn't make anything faster but i was something I had to test for myself.