A few questions about RAM

So i'm almost done building my first (gaming) rig and all I have left to get is the RAM. I'm looking to get 16GB but I have a few questions first:

1. Is it true that anything above 1866MHz will not show a large performance/FPS increase (for gaming)?

2. Are quad channel kits just marketing meaning I should get 2 dual channel kits?

3. How much of a difference does CAS latency make? (I'm planning on getting RAM with a CAS of 9)

(4. Do you see any specific RAM kits that will work extra well with my build?)


If you have any other thoughts or advice please feel free to share with a first time builder. 

Here is my rig:



1. Yes

2. Sort of. Quad Channel is only supported by Socket 2011, so I wouldn't see it as a selling point for a gaming pc.

3. Lower CAS latency means snappier performance out of the RAM, it responds faster.

4. G. Skill RAM would work great with an ASUS motherboard, although I think you would be better off getting 2X8gig over 4X4gig.

I completely agree with everything DemonX09 said apart from CAS latency.

CAS latency can make performance faster, but it's in the order of nanoseconds maybe microseconds; nothing close to being noticeable. Often if you decrease CAS latency, you're having to modify the RAS to CAS timing as well which counters what you're trying to achieve.

It would be better to have a higher frequency kit with stable timings than potentially unstable low latencies and moderate frequencies. But higher clocked memory does not enhance performance much if it's not in conjunction with an APU.

Yup everything above and what DemonX09 is right. The general buying ram rule (i guess) would be get:

-1600mhz ram

-Class 9

-8gb or 16gb

-Dual channel

if you want 16GB ram, on that build just grab 2x8GB kit 1866mhz CL9 ram. Like G.skill sniper or whatnot. ☺

So most of you are saying to get 2 8gb sticks rather then 4 4gb sticks, why is this? Doesn't having all 4 DIMM slots taken increase prefomance or channels?

Is there a preferred or optimal brand for gaming? I heard the Corsair Dominator Platinum is the best out there. Don't know much else.

Anything with good timings and frequency for the price. Never played with corsair but haven't heard any  complaints about them. I've become a g.skill fanatic, everything I've used by them has been top notch, and the warranty backs it up. Great thing about intels is the cpu cache, so try and find something at a higher frequency at a good price.

4x4GB sets aren't that hard on your cpu, it really only matters when you try and overclock. If your cpu can't handle a 4x4 set then you have a dud.

Wait so your saying I should get RAM higher than 1866MHz? (I previously was looking at 2100MHz Mushkin Blackline)

Also what's difference between G Skill X vs Z series? 

1866 would be fine unless the prices are about the same. Off the top of my head I think one is geared towards the 2011 socket.  You would have to look up the details. May or may not have something to do with XMP profiles, I have never looked into it.

with a dedicated gpu, higher speed memory does not increase any gaming performance at all, the problem with high speed memory is often, that it has a high cas latency CL11. For gaming and gpu rendering and stuff you would be better of with lower cas latency ram. i always say CL9 is the sweet spot. 1600-1866mhz is totaly fine. Lower CL is more important then highspeed ram, because how lower the cas latency is, how smaller will the delay be for the cpu to acces the memory module.

Highspeed ram only helps if you are using an igpu or apu based build, on which the igpu or apu, is using the memory speed to work on.

I hope this makes it more clear for you.

Grtz Angel ☺

+1 Perfect

About dual channel, tripple channel, quad channel. only means that the memory controller in the cpu, can speak to 2/3 or 4 memory modules at the same time. Since the i5 you are having has a dual channel controller, this means that the cpu can speak to 2 modules at the same time, thats why 2x8 would be more usefull then 4x4.

Socket 1366 supports triple channel, socket 2011 supports quad channel. as a side note.

Grtz Angel ☺

the problem with high speed memory is often, that it has a high cache latency CL11.

CL is short for CAS latency which is short for Column Access Strobe latency, not cache latency. Cache is in the CPU, not random access memory.

For gaming and gpu rendering and stuff you would be better of with lower cache latency ram.

The effect of a low timings is negligible. The performance of CAS latency on gaming and rendering is very minimal, if it's even observable.

Lower cache latency is more important then highspeed ram, because how lower the cache latency is, how smaller will the delay be for the cpu to acces the memory module.

That's incorrect. The "delay" you're referring to is in terms of one, maybe two clock cycles. But the frequency is in terms of hundreds of clock cycles. For example CL 9 / 2133 MHz= 4.219 ns. CL 7 / 1600 MHz = 4.375 ns.  (These equations are not actually true in terms of real world performance but it illustrates the effectiveness of frequency over timings.)

When you lower the CAS latency from say 9 to 8, what you're doing is reducing the number of clock cycles the strobe requires to access a row in memory. Just because it takes 1 less cycle doesn't mean your performance is faster. But increasing frequency means more cycles occur in a smaller period of time, thus allowing memory to be accessed magnitudes faster (relative to decreasing timings at least).

highspeed ram does not effect anything in gaming, with a dedicated gpu. and low CAS Latency is still more important then highspeed ram.(especialy with video editing and stuf) But it does not realy matter afterall. its just a fairy tail, that high speed ram gives you an performance boost in anything. lol ☺ if you got 2400mhz cl11 ram and you put it up against 1866mhz cl9 ram, you will realy see no diffrence in performance at all, just gonne pay a shit load more cash for a higher frequency number, which does not give any more real world performance, and that is basicly my point.☺

I agree that higher frequency RAM, say 2133 MHz, doesn't have an observable effect on performance compared to say 1600 MHz.

But CAS latency's effect on performance is also negligible, in fact more so than frequency. Like I said in a previous post, CAS latency is simply the number of clock cycles it takes for a row in memory to be accessed. It gives no information on how much time it takes for information to be accessed. The only way to find out how long it will take is to factor in CAS latency, RAS to CAS delay, your RAM's frequency and even the row precharge time. And the most significant factor is frequency, not CAS latency.

So latency is not more important than frequency when it comes to rendering video or gaming. If by some apparition your RAM's timings do enhance performance slightly, the degree of increase will be so small it may as well be negligible.