Maximum PC

Is there really any difference between the different brands of Memory? What should I look for? Should I just base my decision on Cas Latency, price and color?

Why do you think AMD cards are better at video editing then Nvidia?
What are you basing that on?

OK, I’m going to ask the question that has to be asked!! If Corsair Vengeance isnt worth the price why does MaxPC use it in most of their builds? ?

If I use DDR3 1866 memory will it run at 1866 or 1600? Do I have to change the BIOs to get it to run at 1866?

Which is faster DDR3 1866 CL11 or DDR3 1600 CL9?

There is one way to determine whether a kit might be better than another, and that is to look at the calculable latency of the kit.

2000 x (CL / Speed ) = Latency in nanoseconds (ns)

Thus for the three kits

DDR3-1333 9-9-9 has a latency of 13.5 ns
DDR3-1600 10-10-10 has a latency of 12.5 ns
DDR3-1866 11-11-11 has a latency of 11.79 ns

This latency essentially tells us which kit is fastest at non-sequential reads. Non-sequential reads are important in a lot of variable scenarios, such as video games whereby the user could perform one of a billion different actions and as such different elements of the memory have to be loaded.

The downside of this test is that it does not take into account consecutive reads. When dealing with conversion, video editing, or anything that requires a large dataset to be read sequentially, we have to look at how long reads are processed.

The way to check this with DDR3 is as follows:

Cycle time in ns = 1000 / (Memory Speed / 2)
Bit time in ns = 1000 / Memory Speed

The time to read a single word of data (word is a technical term meaning 64 bits) is given by the Cycle Time multiplied by the CL. The time to read eight words is the Cycle Time multiplied by the CL then add seven lots of Bit Time. Let us go through the memory kits with this method.

DDR3-1333 9-9-9 has a Cycle Time of 1.5 ns and a Bit Time of 0.75 ns
The time to read one word is 1.5*9 = 13.5 ns
The time to read eight words is 13.5 + 7 * 0.75 = 18.75 ns

DDR3-1600 10-10-10 has a Cycle Time of 1.25 ns and a Bit Time of 0.625 ns
The time to read one word is 1.25 * 10 = 12.5 ns
The time to read eight words is 12.5 + 7 * 0.625 = 16.875 ns

DDR3-1866 11-11-11 has a Cycle Time of 1.07 ns and a Bit Time of 0.536 ns
The time to read one word is 1.08 * 11 = 11.79 ns
The time to read eight words is 11.79 + 7 * 0.536 = 15.54 ns