I usually put higher speed memory in my boxes as CAD is my "9 to 5" thing. However, I don't quite "get" the mindset on gaming and memory.... peeps will argue vehemently about one GFX card having a singe digit % advantage over another and then say that same % fps advantages from memory speed don't matter . Comparing DDR3-1600 and DDR3-1866 with a $2 price difference, and looking just at gaming related benchmarks. The cost difference is 2.27% for the RAM and 0.13% on a $1500 system
http://www.youtube.com/watch?v=W0L_KFKJYvg
3D Mark - 1.00 % advantage
BF3 - 5.2% advantage in max frame rates
Far Cry 3 - 1.7 % advantage in avg frame rates
So is a 0.13% cash investment worth those 1% to 5.2% improvements ?
With a $2 system cost increase, going from DDR3-1600 to DDR3-1866 is easy to justify. A jump to 2133 is a bit harder .... that's a 1.9 % increase in system cost and gives ya 1.9% increase in 3DMark .... remember though that the fps differences are usually in single digits and this is within the margin of error. Above that point ya usually see some diminishing returns as CAS starts dropping .... what's faster 2400 CAS 11 or 2133 CAS 9 ?
9/2133 x 1000 = 4.22 nanoseconds
11/2400 x 1000 = 4.58
So the CAS 9 2133 is faster
$160 for Mushkin CAS 9 DDR3-2133 looks to me as the best buy for hi performance RAM
http://www.newegg.com/Product/Product.aspx?Item=N82E16820226420
The Corsair Vengeance Pro sure do look perty but they come up short on price and specs
$170
http://www.newegg.com/Product/Product.aspx?Item=N82E16820233542