Question Memory Choice for X299 motherboard

[braxus]

I have a Gigabyte Gaming 7 X299 motherboard which I plan to upgrade the CPU to a new 9920X in the future. I'd like to upgrade the ram in the motherboard, since Im only running a generic Samsung 8GB stick at the moment. So Im looking at two different DDR4 sticks. Both GSkill. One is the Ripjaws V with a 3200 speed and 14 latency. The other is a Trident Z with a speed of 4000 and latency of 19. Now a latency from 14 to 19 is a big jump, so am I going to see any improvement going to the 4000 speed over 3200? I will be using 2 16GB sticks to start, and add more in the future. I do 4K video editting on my computer, so speed is a factor. I have 8 slots I can fill, but for budget reasons I'll start with 2 sticks. Not concerned whether its dual channel or quad channel. I"d want mine to be XMP capable as well, so it can be overclocked to its rated speed.

 

[sizzling]

Buying RAM now and adding more later is risky, RAM is best used in matched kits to avoid issues especially where the system supports quad channel. It seems odd to worry about RAM speed and then state you are not worried about dual/quad channel which will most likely have a bigger impact on performance.

As for latency vs speed for your use I will let someone with more video editing knowledge answer that one.

 

[Darkbreeze]

I will be using 2 16GB sticks to start, and add more in the future.

No, you really DON'T want to do that. Especially not on a quad or higher channel system. Well, not on any system for that matter. If you think you will need 64GB, then BUY 64GB in ONE kit from the start. Otherwise you are just opening the door wide open to problems later. Adding mixed memory didn't used to be as big of an issue, and adding more of the same memory later didn't either. Now though, these kits and sticks undergo major changes to their composition even when the same part number is used that often they will simply not work together at all later, or won't work together at the advertised speed or timings because there are too many differences in the makeup of the stick for them to play nice.

Here is an example. Not your platform, but it is a perfect example not of the fact that mixed memory is a major crapshoot when you try to add different memory later, but that's a problem too in much the same way, well exactly the same way actually, but in the fact that even if you buy an identical kit later, you may not be getting identical sticks and these days we see more and more issues with memory not working with sticks that were purchased previously. If you see in the following link, three completely different memory configurations, ALL of them share the exact same part number. I can verify for a fact that none of those three part numbers will play nice when tossed into the same machine together.

They ALL use different ICs (Memory chips), two of the three are Dual rank, while one is Single rank. Two are double sided, while one is single sided. Two use 4GB dies, while one uses 8GB dies. All three sticks have different secondary and tertiary timings, and that's one of the places where memory gets into trouble when you try to use sticks that were not all from the same kit and production run, together.

https://forums.tomshardware.com/threads/amd-ram-compatibility.3210050/#post-19785792


You COULD get lucky, but you just as well could be looking at a major headache later, like MANY users we've seen over the last couple of years.


Personally I would recommend the 3200mhz sticks at CL14. Those are going to be as fast as you will see any actual benefit from in practially anything not strictly a benchmark, AND, if you DO add more than two modules at some point you will likely have a very hard time getting four or more sticks to run at 4000mhz anyhow. Manufacturers don't guarantee that you can get very high speed sticks to all run on a given board. They only guarantee that you can get the default JEDEC SPD of 2133mhz, or whatever the standard default speed is for the chipset, to run with more than two sticks. It can be done most of the time, but usually not with sticks that fast so if you have to drop the memory clock down to 3600 or 3200mhz anyhow, it's pointless to buy them in the first place. Plus, I doubt you'll find a quad channel 4000mhz kit in any case and that is for a reason.

I don't see ANY consumer kits on the market for 4 x16GB 4000mhz sticks, because it's very improbable that you'll get four sticks to run at that frequency anyhow.

 

[braxus]

Ok. See next post below

 

[braxus]

Just noticed this option: G Skill Trident Z 64GB (8 Sticks of 8GB) of 4000 speed latency 18. Its expensive, but Im assuming all 8 sticks are matched? How reliable with these sticks be at 4000? Or should I still stick with the 3200 sticks?

 

[Darkbreeze]

It's still a crapshoot. The more modules, the more chances there are for something to not play nice. It can work. We had a guy recently with an 8 x16GB kit on the same platform with an X299-A or the same board you have, I can't remember which it was and I just spent about fifteen minutes trying to find that thread for you but couldn't find it. Seems some links are borked after the change of forum software. The migration just wiped out many of the old links I guess, and it sure messed up the Google results when trying to search for things using keywords that used to bring them right up on the old forum

Anyhow, his first kit had one module that wouldn't run at the right speed. We spent days trying to work it out. Sent them back, got another kit. Two sticks this time. Finally on the third, and much more expensive kit, we were finally able to get them to all run and those were only 3200mhz sticks.

The Trident Z sticks, especially the CL14 models, are the highest end memory you can get. Any 3000 or 3200mhz stick with a CL14 latency is using a Samsung B-die IC, which is the cream of the crop.

If you can get the model number of the kit you are looking at I'd be glad to see what I can find out about them.

 

[gskill support]

https://www.gskill.com/en/configurator?manu=54&chip=3030&model=3043

DDR4-3733 is around the best you can get unless a BIOS update can improve that. Pick any from the list above for guaranteed results.

High frequency will still be better than lower latency. It is natural for latency to increase with frequency.

 

[Darkbreeze]

That's, not actually true. Not in every case anyhow. Lower speed memory with a lower true latency will be faster. In some cases, if the frequency is fast ENOUGH, it can overcome the latency and have a lower true latency, but it has to be awfully fast if you have very low latency sticks with very tight timings.

Memory specifications and overclocking can be very deceiving. If you're unaware, here's the formula for "True Latency":

1 / Frequency (not DDR) x Latency = True Latency (nanoseconds).

Stock 3200 @ 14 is faster than Stock 3600 @ 16:

1 / 1.600GHz x 14 = 8.75nS
1 / 1.800GHz x 16 = 8.89nS

Stable Overclock with 3733 @ 16 is faster:

3733 @ 16 is 1 / 1.867GHz x 16 = 8.57nS

By calculating True Latency, when experimenting with memory overclocking, it becomes much easier to determine with greater consistency, where you might expect to find that elusive fuzzy-grey edge of stability.

Accept for applying excessive or prohibitive voltages above 1.35, which can potentially damage your processor's IMC, even with the best chips, any Frequency / Timing combinations that result in True Latencies below about 8.5'ish to 8.4'ish may be unstable, or unbootable.

-Computronix
Author - Intel temperature guide