How much RAM do you need: 8GB DDR3/1600 OR DDR3/1866

How much RAM do you need, how many channels, and what speed? From our experience, and based on today’s RAM prices and capacities, we recommend 8GB of DDR3/1600. Everyone knows that 2GB is not enough RAM today. And while 4GB is OK, why stop there when 8GB isn’t much more? At press time, 8GB of DDR3/1600 fetched roughly $40 while 4GB is about $30.

How much RAM do you need: 8GB DDR3/1600 OR DDR3/1866

Should you buy more RAM than that? Only you can answer that question. If your applications are RAM hogs or you tend to multitask, additional RAM can’t hurt.

There’s one more pesky problem, though: How many memory channels do you really need? Is it worth paying the extra surcharge for a quad-channel setup or is dual-channel enough? To find out, we took our trusty LGA2011-based zero-point, set it to bone-stock clock speed and tested it with 8GB of DDR3/1333 in quad-channel, dual-channel, and, well, single-channel, using various benchmarks. Some of the benchmarks are GPU-limited and others are CPU-limited to make a point that memory bandwidth won’t make a difference in many of your applications. Stepping from quad to dual doesn’t hurt much, but going to single will definitely take a bite out of performance, although not as much as you would suspect. In fact, upping the memory speed from DDR3/1333 to DDR3/1866 actually erased the difference in the apps that seem to like bandwidth the most: encoding.

Why does memory bandwidth make nary a difference in the vast majority of apps? Thank the huge caches in today’s CPUs. The only time you really want to go all out on memory bandwidth is when you’re intending to game with integrated graphics.

3DMark 11 overallX5,794X5,764X5,634
x264 5.0 HD Pass 1 (fps)85.883.474.4
x264 5.0 HD Pass 2 (fps)1918.918.8
SiSoft Sandra (GB/s)
Stitch.Efx (sec)906898919
ProShow Producer 5.0 (sec)1,5531,5861,732
Cinebench 11.510.210.210.02
We used an Asus Sabertooth X79 motherboard, 8GB of DDR3/1333, GeForce GTX 690, OCZ Vertex 3 SSD, and 64-bit Windows 7 Professional for testing both CPU configurations.