Which 16 GB RAM should I get?

[Tweed]

Corsair Vengeance LPX 16GB (2 x 8GB) DDR4-2666 Memory CAS 16

or

Corsair Vengeance LPX 16GB (2 x 8GB) DDR4-2133 Memory CAS 13

Still unsure if I should go 4x4 or 2x8. Let me know.

 

[patrick47018]

Definitely the 2666 CAS 13. You want high MHz(speed) AND low CAS(latency). 2x8GB is a fine choice, unless for some reason 4X4GB is way cheaper.

 

[rhysiam]

Patrick is absolutely right that the faster and lower latency memory is better all else being equal... no question. But if you're paying a lot extra for the faster memory, you're likely to be better off investing your money elsewhere. Faster RAM doesn't make a huge difference, so if buying faster RAM leaves you less money for something like an SSD, or reduces your GPU budget, I'd go cheaper RAM myself. But no doubt, if they're priced similarly it's a no-brainer.

Just a quick note on the 2x8 vs 4x4 question. If you're on a dual channel platform (non "extreme" processors on the Z99, Z170 motherboards, etc), 2x8 is definitely the way to go. If you're on a Haswell-E or other quad memory channel platform (X99 motherboard with a 5820K/5930K/5960X), then 4x4GB will in theory give you slightly faster memory, because the system can access all four channels at once. Again in the real world it's rarely noticeable, but on a pure performance basis 4x4GB will give you faster memory if (and only if) you're on a quad channel platform like the Intel-E gear.

 

[Tweed]

Sorry I just updated it. I mean 2133 CAS 13, 2666 CAS 16.

Current so far build. http://pcpartpicker.com/p/PB2GCJ

 

[rhysiam]

It's not entirely accurate, but the quick-and-dirty calculation for absolute latency is CAS timing / Frequency. That gives the actual latency for both at just over 6ns. So they both have (effectively) the same latency, but the 2600 kit has a higher frequency meaning more throughput. The second kit is better, but I (personally) wouldn't pay more than $10 for that faster kit.

You're on a Z170 mobo with a dual memory channel, so 2x8 is for sure the way to go. (Unless, as Patrick rightly notes, you can somehow get a bargain on a 4x4).

 

[Tweed]

It's not entirely accurate, but the quick-and-dirty calculation for absolute latency is CAS timing / Frequency. That gives the actual latency for both at just over 6ns. So they both have (effectively) the same latency, but the 2600 kit has a higher frequency meaning more throughput. The second kit is better, but I (personally) wouldn't pay more than $10 for that faster kit.

You're on a Z170 mobo with a dual memory channel, so 2x8 is for sure the way to go. (Unless, as Patrick rightly notes, you can somehow get a bargain on a 4x4).

2133 CAS 13, 2400 CAS 14, 3000 CAS 15, or 2666 CAS 16

 

[Tradesman1]

Go for 2x8GB 2666/15 the Ripjaws V

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231892

 

[Tweed]

Go for 2x8GB 2666/15 the Ripjaws V

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231892

Reasoning? Why 2666? Why G.Skill over Corsair? Just curious

 

[Tradesman1]

You said "Sorry I just updated it. I mean 2133 CAS 13, 2666 CAS 16" , Isuggested better 2666 with a 15CL, better performance. GSkill over Corsair - Gskill typically has stronger sticks with more OC headroom, also with Corsair you pay premium for name - not performance - they are good sticks yes, but going into a new build, might as well get the best you can