Differences between 3200C14 and 3600C17 as well as CPU compatibility

[anandtechreader]

Hello, DDR4-3600 seems to be faster than DDR4-3200 due to higher number. However, I read that memory with lower C value is faster. So, in this case, is DDR4-3200C14 faster or 3600C17 faster?

I asked G.skill to recommend me memory for i9-7900X. One technician recommended 3600C17 and the other recommended 3200C14. The former mentioned that 3600C17 is faster if I OC and there is no problem with stability. However, the other guy recommended 3200C14 and said that even my motherboard does not list 3200 but 3600 as one of the compatibility memory type, I can use 3200C14 stable by just enabling OC XMP in the Bios. Who is correct?

The first technician mentioned that both memory kits can be used also in Intel 8700K and the Threadripper. However, the 2nd technician mentioned that I use a separate product. Who is correct?

 

[BonzaiDuck]

Hello, DDR4-3600 seems to be faster than DDR4-3200 due to higher number. However, I read that memory with lower C value is faster. So, in this case, is DDR4-3200C14 faster or 3600C17 faster?

I asked G.skill to recommend me memory for i9-7900X. One technician recommended 3600C17 and the other recommended 3200C14. The former mentioned that 3600C17 is faster if I OC and there is no problem with stability. However, the other guy recommended 3200C14 and said that even my motherboard does not list 3200 but 3600 as one of the compatibility memory type, I can use 3200C14 stable by just enabling OC XMP in the Bios. Who is correct?

The first technician mentioned that both memory kits can be used also in Intel 8700K and the Threadripper. However, the 2nd technician mentioned that I use a separate product. Who is correct?

"I read that memory with lower [CAS-latency] is faster." This means that DDR4-3200 CAS=14 is faster than DDR4-3200 CAS={15, 16 or 17}. DDR4-3600 C17 will still be faster than DDR4-3200 C14.

Are you sure what processor and chipset you plan to use? You mention i9-7900X (and X299 chipset). Then you mention the i7-8700K (and Z370 chipset), and you also talk about ThreadRipper. sometimes, you'll find G.SKILL that will fit all three. But why don't you settle on the processor and chipset, and then choose the RAM accordingly? For instance, the i9-7900X with X299 motherboard has a wide variety of TridentZ and RipJaws models that fit up to 3733 Mhz, and I know this is also true for the i7-8700K/Z370.

Pick your CPU; pick your motherboard; then go to the G.SKILL website, run the RAM configurator with the motherboard info andl pick your RAM.

 

[anandtechreader]

Sorry my situation is a bit complicated. Let's take it one by one.

Case 1:

I look for RAM for i9-7900X and told G.skill the motherboard. They recommended some RAM Kit. One guy suggested 3200C14 and the other suggested 3600C17. Not sure who to listen to. I went to ASUS to cross check which G.skill's RAM Kits are compatible with the motherboard I am interested in. Those RAM recommended by G.skill are not listed.

Q1: Should I choose 3200C14 or 3600C17? The workstation is not for playing games but for computationally intensive simulations with CUDA. High memory bandwidth between CPU and GPUs is desirable.

Q2: Since G.skill's said that the Kits they recommended are compatible with the motherboard I want, shall I rely on them even the motherboard's QVL does not list the memory Kits G.skill recommended.

 

[BonzaiDuck]

Sorry my situation is a bit complicated. Let's take it one by one.

Case 1:

I look for RAM for i9-7900X and told G.skill the motherboard. They recommended some RAM Kit. One guy suggested 3200C14 and the other suggested 3600C17. Not sure who to listen to. I went to ASUS to cross check which G.skill's RAM Kits are compatible with the motherboard I am interested in. Those RAM recommended by G.skill are not listed.

Q1: Should I choose 3200C14 or 3600C17? The workstation is not for playing games but for computationally intensive simulations with CUDA. High memory bandwidth between CPU and GPUs is desirable.

Q2: Since G.skill's said that the Kits they recommended are compatible with the motherboard I want, shall I rely on them even the motherboard's QVL does not list the memory Kits G.skill recommended.

Perhaps I might have elaborated some more.

Look at it from the viewpoint of either the motherboard maker or the RAM maker. There are so many boards on the market with different chipsets utilizing a certain generation of various CPUs. Similarly, for the motherboard maker, there are a large number of RAM makers each making a formidable number of different models of DDR4 RAM. Therefore, the mobo manufacturer can only do a representative sample of tests for a manageable list of RAM kits, and the RAM maker can only test a sample of so many motherboards.

You may have to extrapolate from the QVL list of the mobo, and the certification list of motherboards used by G.SKILL. For instance, you might find that the motherboard QVL list includes a RipJaws or TridentZ ram-kit model of DDR4 3000 RAM. But you want to verify that a similar model spec'd at DDR4 3400 fits your board. Usually, even if the DDR4 3400 isn't on the QVL, the inclusion of the slower-speed kit should allow you to conclude that the hardware works together.

G.SKILL might only provide compatible RAM listings for four motherboards requiring DDR4 RAM which span their model lines of all such boards. I could verify that three models of ASUS Maximus, an ASUS Deluxe and an ASUS Pro board with a Z170 chipset had G.SKILL compatible memory lists that were very long, but G.SKILL had not tested my Sabertooth Z170 board. But you could be sure that the Sabertooth would work with RAM that fit the other boards.

IF G.SKILL tech support tells you that certain memory of theirs will work with your motherboard, it should be good enough assurance that it does. You don't necessarily have to find those particular RAM specifications on the motherboard QVL.

Also, others here will tell you that faster or slower RAM within that speed range won't make a great difference in overall performance. If you want to spend more money on RAM and want the fastest possible, get the faster RAM. Just make sure you have an idea from other users if there is a trick or some problem reaching the spec RAM speed on a particular group of motherboards and BIOS versions. If, on the other hand, you feel comfortable with buying DDR4-3200, you can comfort yourself (as have I) that the latencies with CAS 14 are among the tightest timings you'll find for all other RAM spec'd at that speed, no matter who makes it.

 

[anandtechreader]

Thanks. I contacted G.Skill using two different methods. The strange thing is that people who replied by email advised against 3600C17 but recommended 3200C14. People who replied via chat said either one is fine but recommended 3600C17 if I want to see "big noticable" performance when I OC. He said that to use either RAM, I have to OC.

 

[BonzaiDuck]

Once again, you may have misunderstood them. If you look here and there at either a reseller web-site or the manufacturer web-page for the motherboard, they may show in the specifications the various speeds of RAM that will work, and these may be expressed (for instance) as "3200 (OC)." That is, the chipset or CPU spec might show a lower number like 2133. (And my examples are out of date, if you motherboard is a later generation than my Z170).

This simply means that the motherboard will set the memory at the base spec speed without specifying "XMP" in the BIOS setup. If you select "XMP" in BIOS, the board will choose the memory spec speed (for instance) DDR4-3200. But you don't need to spend time tweaking the RAM manually.

If you wish, I can poke around in the web-pages for you and render an opinion. What is the make and model of your motherboard?

[A few minutes later]: I'm looking at X299 motherboards for i9 processors like the i9-7900X. More specifically, I'm looking at ASUS motherboards from PRIME X299-A through ROG STRIX X299-E Gaming boards.

In summary, the CPU memory spec is DDR4-2666. The motherboard/chipset spec maximum is DDR4-4000 (OC). I could check for each and every board, but I'd surmise that G.SKILL kits certified for any one of these boards likely work with all of them. Yet, we can narrow it down to be sure.

What size of memory kit to you think you want? 16GB? 32GB? 64GB?

 

[anandtechreader]

Thanks. I have a general question. I am considering 32GB (16GBx2) or 64GB (16GBx4). How likely will there be a problem if I get the 64GB kit now and if needed, get another 64GB kit later to make it 128GB? Some people mentioned that if I buy RAM separately, there is a possibility that there will be issues due to "different bins". What is the chance of that? 128GB RAM is just too expensive and I may not need that much. However, if I buy 64GB now and need 128GB later, I may waste the 64GB and have to buy another 128GB as one kit later.

 

[BonzaiDuck]

I looked at the QVL list for that WS X299 Sage board. There are several G.SKILL DDR4-3000 kits that were tested, and several slower kits. Look at the last character sequence in the model code: GVK, GTZB, GRK, GRR, GTZR, GVKB. Some of these are "Q" (quad) kits, some are "D" (dual) kits, some are Q2 (double-quad) kits. There's a good chance that you could buy two "D" kits and configure them as quad-channel. [someone else can correct me if wrong. But in some cases, the dual kits are described as appropriate for "Z170 and X99."]

Look at the model codes; extrapolate by finding the 3200 and 3600 kits with the same model code. There are even TridentZ (GTZB or GTZR) kits which work, even if sold as dual-channel.

When buying two separate kits of the same model, G.SKILL had told me per my TridentZ DDR4-3200 dual kits that they "couldn't support" kits that weren't part of a matched set at spec speed, but if I ran the kits at DDR4-3000 they would support them. I assume this means for purpose of "RMA replacement." I rolled the dice anyway, and found that the two kits run at full spec together through 1000% HCI Memtest64.

After that, keep in mind what I said about using two separate kits. Will 128GB really make a difference over having a 64GB kit? Are you willing to chance the inconvenience of RMA-refund if you buy two identical kits and they don't run at the spec XMP speed? If you are willing to accept a possibility of inconvenience, you could buy 64GB now, and 64GB later.

Be sure to buy kits with 16GB modules. I think it would be short-sighted to buy a 4x8GB 32GB kit to run as quad-channel, and then decide you need 64GB, when you could initially get 4x16GB = 64GB to run as quad-channel.

That motherboard will handle RAM spec'd to DDR4 4000. With that much RAM, I personally would be fine with DDR4 3200 kits -- perhaps 4x 16GB or 2x 16GB for either 64 or 32 GB total.

Hopefully, everything I've said here is also consistent with what the G.SKILL techies told you. If not, follow their recommendations over mine.

 

[anandtechreader]

Thanks. So in this case 3200C14 would be better? Is the RMA-REFUND period a month? What if I use 64GB now without problem but few months later after the RMA-REFUND period, I find that I will need 128GB RAM?

How likely will these RAM Kits be compatible with PCIe 4.0 and 5.0 systems? How the performance will be like when DDR5 RAM comes out five years later?

BTW, do you know if the Samsung 960 EVO and 960 PRO are of size 2242/2260/2280/22110? It is not written on the specs and Samsung people told me that he has no idea!

 

[IntelUser2000]

How likely will these RAM Kits be compatible with PCIe 4.0 and 5.0 systems? How the performance will be like when DDR5 RAM comes out five years later?

RAM kits have no relation to PCIe versions on compatibility. The type of chipset you get does.

According to Tomshardware, dual rank modules are better than single rank. That's one more thing to worry.

https://www.tomshardware.com/reviews/best-ram,4057.html

BTW, do you know if the Samsung 960 EVO and 960 PRO are of size 2242/2260/2280/22110? It is not written on the specs and Samsung people told me that he has no idea!

Most M.2 SSDs are 2280.

 

[anandtechreader]

RAM kits have no relation to PCIe versions on compatibility. The type of chipset you get does.

According to Tomshardware, dual rank modules are better than single rank. That's one more thing to worry.

https://www.tomshardware.com/reviews/best-ram,4057.html



Most M.2 SSDs are 2280.

Thanks. So, how likely will the chipsets that come out when the PCIe 4.0 5.0 components arrive will be compatible with the RAM kits that have been mentioned in this thread? I am trying to decide if I should invest that much money on these expensive DDR4-RAM kits. If they are less likely to be supported well when PCIe 4.0/5.0 systems come out or DDR-5 will perform significantly faster, I may not invest that much.

If I use dual rank modules, it means I can only put 64GB (8GBx8) max on the motherboard?

 

[BonzaiDuck]

Thanks. So in this case 3200C14 would be better? Is the RMA-REFUND period a month? What if I use 64GB now without problem but few months later after the RMA-REFUND period, I find that I will need 128GB RAM?

How likely will these RAM Kits be compatible with PCIe 4.0 and 5.0 systems? How the performance will be like when DDR5 RAM comes out five years later?

BTW, do you know if the Samsung 960 EVO and 960 PRO are of size 2242/2260/2280/22110? It is not written on the specs and Samsung people told me that he has no idea!

My personal inclination -- the 3200C14 should be fine. With some resellers (we're talking about reseller RMA and not manufacturer RMA) -- it is a month. But it is the second kit that concerned me about RMA, if you buy them and aren't satisfied. You'd have a month to RMA the second kit after you bought it. If it were me personally, I could see myself pulling the string on 3466 or 3600 RAM in the same model line. I would consider it, anyway. But I still don't think it should matter that much. If the G.SKILL 3200's run at 14-14-14, I wouldn't bother with the higher spec.

Either 960 EVO or PRO will fit that board -- one way, or the other. It has the onboard slots, and you can get a PCIEx4 card to install it for $30. I'm pretty sure those Sammy drives will fit the motherboard

Check the motherboard specs. If the board supports PCIE-bifurcation, you can get a PCIEx8 card to fit four 960's in a slot offering 8x lanes, and run them as RAID0 or maybe RAID5. The board specs tell me you should have everything among those options:

1 x M.2 Socket 3, with M key, type 2242/2260/2280/22110 storage devices support (PCIE 3.0 x 4 mode)
1 x M.2 Socket 3, with M key, type 2242/2260/2280 storage devices support (PCIE 3.0 x 4 mode)
8 x SATA 6Gb/s port(s)
2 x U.2 connector*1

You're spending at least $2,300 (approx.) on just the three components of processor, motherboard and RAM. You can spend as much as you want -- I can think of all sorts of ways. Here and there, I might covet a $500+ motherboard and $1,000 processor, but I always seem to find my best fit at "second tier" parts.

How do you plan to cool the processor? How many graphics cards to intend to install?

ALSO. I read the response to your query about RAM and PCIE version. There's otherwise no connection between RAM spec and the PCIE bus. I think what you're asking is as follows: "Will DDR4 RAM still be used in motherboards appearing later with a PCIE 4.0 [etc.] standard spec?

That's a roll-the-dice and take-your-chances proposition, either way. [Anyone need to buy some DDR3 G.SKILL modules I don't need anymore? Well, that's the choice: put up the old parts on the Anand "For Sale or Trade" forum. I think I'll put up a list of my own. ]

 

[IntelUser2000]

Thanks. So, how likely will the chipsets that come out when the PCIe 4.0 5.0 components arrive will be compatible with the RAM kits that have been mentioned in this thread?

Again, RAM has NOTHING to do with PCIe.

 

[anandtechreader]

I don't know what kind of cooler is the best for the 7900X. I want a silent or almost silent system. Some suggested water cooling but there is a potential risk of leakage. Others suggested air cooling is fine especially if I don't OC. If I use DDR4-3200 or 3600 RAM, I will have to OC via the bio setting. 1GPU for the time being but I may add more later.

>ALSO. I read the response to your query about RAM and PCIE version. There's >otherwise no connection between RAM spec and the PCIE bus. I think what you're >asking is as follows: "Will DDR4 RAM still be used in motherboards appearing later >with a PCIE 4.0 [etc.] standard spec?

Yes.

 

[BonzaiDuck]

I don't know what kind of cooler is the best for the 7900X. I want a silent or almost silent system. Some suggested water cooling but there is a potential risk of leakage. Others suggested air cooling is fine especially if I don't OC. If I use DDR4-3200 or 3600 RAM, I will have to OC via the bio setting. 1GPU for the time being but I may add more later.

>ALSO. I read the response to your query about RAM and PCIE version. There's >otherwise no connection between RAM spec and the PCIE bus. I think what you're >asking is as follows: "Will DDR4 RAM still be used in motherboards appearing later >with a PCIE 4.0 [etc.] standard spec?

Yes.

That's the trade-off for optimizing your decision and expenses. The more you spend, the more you'll have to dispose of when you want to upgrade significantly.

Have you purchased all of your essential parts yet -- CPU? Motherboard? You're apparently trying to settle on RAM. You've apparently considered a Coffee-Lake unlocked i7-8700K system, but you're focused on this WS X299 Sage motherboard.

You could pay extra for a binned and de-lidded CPU -- relidded with a liquid metal TIM -- from Silicon Lottery. That would reduce your temperatures by between 12C and 25C. If you do that, you could definitely be well-positioned to do some great air-cooling, but it would be a large heatpipe cooler, and I would carefully choose it through cross-referenced comparison reviews of as many models as possible. If I were to do something like that now, I'd consider my ThermalRight LG Macho, but I would revisit the comparisons. Or -- I might think about an NXZT Kraken X62 AiO water-cooler. With what you intend to invest, you'd also like to control costs, so you might opt for "very effective" but simple cooling over either a kit or custom-chosen parts -- again, with the risk you mention, especially if you haven't had the experience doing that.

 

[IntelUser2000]

ALSO. I read the response to your query about RAM and PCIE version. There's >otherwise no connection between RAM spec and the PCIE bus. I think what you're >asking is as follows: "Will DDR4 RAM still be used in motherboards appearing later >with a PCIE 4.0 [etc.] standard spec?

I misunderstood you on your post. I apologize.

PCIe 4.0 may appear as early as 2019. It's highly likely we'll see DDR4 used as system memory for that generation. I think DDR5 may be quite far off.

The current hierarchy for memory is DRAM, then SSD, backed by a capacious HDD. The eventual plan is for HBM to be on-package with the CPU, DRAM for expansion, and if non-volatile memory like 3D XPoint works out, you'd have very fast storage-memory, and TLC/QLC SSDs for the rest. That should happen within a decade. We may see such consumer setups as early as 5 years.

The new tier will make it much faster than any DDR5 memory will allow, and may mean the development can be delayed. Current roadmaps say post-DDR4 in consumer platforms coming later than 2020. DDR3 lasted a long time. It was back in 2007-2008 when it was used. 2016 with Skylake DDR4 appeared. I think even 2021 may be optimistic.

 

[anandtechreader]

No problem. How likely will PCIe 4.0 components be available earlier 2019? If it will be available in less than a year and the performance especially for GPU CUDA computations will be significantly improved, perhaps I should not build such an expensive computer now. Except for the case, I have not ordered other components yet.

 

[IntelUser2000]

It's practically Intel driving the standards, and it doesn't look like it'll be anytime before 2019 when desktop Intel Icelake generation will arrive. That would be the earliest when PCIe 4.0 would arrive, because the controller would have to be built into the CPU die. If its not Icelake, you are talking further out. Maybe 2021 with Alderlake or whatever they decide to call it. PCIe 5.0 is even further away. I don't believe in some projections saying 4.0 will be very short lived. Either they'll bring 4.0 and last many years before 5.0, or they'll decide to "skip" 4.0 and we'll use 5.0 for many years.

Does CUDA already rely on PCIe throughput for performance? Maybe there are benchmarks out there comparing between PCIe 3.0 x8 and x16 speeds. If its not significant, PCIe 4.0 won't do much either.

 

[BonzaiDuck]

No problem. How likely will PCIe 4.0 components be available earlier 2019? If it will be available in less than a year and the performance especially for GPU CUDA computations will be significantly improved, perhaps I should not build such an expensive computer now. Except for the case, I have not ordered other components yet.

The sense of it I have coming from criticisms of others here to myself, is that greater PCIE bandwidth is less and less an advantage for each successive increment. I built my replacement home server with an eye toward PCIE 3.0 capability, and picked what seemed then -- and now -- to be a great SATA storage card without hardware RAID to use for a drive pool. I should be able to cache the drive pool to an NVME SSD or to RAM. The server could spare 8GB of the total 16GB.

But I'm not that familiar with what you're doing to or with your graphics card. Bitcoin mining?

Think of it. An i7-8700K Z370 system would have six cores and twelve threads. You could probably socket up to 64GB of RAM. The limitations on the PCIE (CPU) and PCIE (chipset) lanes still enable one to utilize NVME to the hilt. But if you really think you can fully utilize that WS Sage board, I would be interested in how it comes out. I'd be interested in the outcome either way.

 

[anandtechreader]

Some people think that since PCIe4.0 is short lived, manufacturers may skip it.

Although x16 speed has no advantage for gamers, people doing CUDA computing mentioned that it makes a big different. So it is important to know when PCIe 4.0 and PCIe 5.0 systems with be available for purchase.

Given that the 7900X has the Meltdown and Spectre bugs, not sure if it is still a good idea to spend on such expensive CPU.

 

[BonzaiDuck]

Some people think that since PCIe4.0 is short lived, manufacturers may skip it.

Although x16 speed has no advantage for gamers, people doing CUDA computing mentioned that it makes a big different. So it is important to know when PCIe 4.0 and PCIe 5.0 systems with be available for purchase.

Given that the 7900X has the Meltdown and Spectre bugs, not sure if it is still a good idea to spend on such expensive CPU.

But those threats have been addressed regardless of platform or generation. I don't think that's a good decision criterion.

 

[anandtechreader]

Actually I am still drawn between 8700K and 7900X but lean towards the latter. I am a Scientist. I do need a powerful computer for work. I haven't built a computer for almost 20 years. At that time, Intel CPU came with a fan and there was no GPU. It was not that complicated to build a computer. I don't keep up with hardware technologies. So all these things are unfamiliar to me.

 

[whm1974]

Actually I am still drawn between 8700K and 7900X but lean towards the latter. I am a Scientist. I do need a powerful computer for work. I haven't built a computer for almost 20 years. At that time, Intel CPU came with a fan and there was no GPU. It was not that complicated to build a computer. I don't keep up with hardware technologies. So all these things are unfamiliar to me.

I'm no expert, but shouldn't you be looking at ThreadRipper or Xeons instead?

 

[BonzaiDuck]

I'm no expert, but shouldn't you be looking at ThreadRipper or Xeons instead?

A____reader hasn't responded yet.

I'm just not clear on what he's doing. I remember running statistical analysis software on 80386 desktops. Eventually, I might ask "what sort of computational capability would you need to simulate nuclear explosions, such as the work they do at Los Alamos?" I've seen people build dual Xeon hexa-core systems that would ordinarily seem to be way overpowered.

 

[anandtechreader]

I'm no expert, but shouldn't you be looking at ThreadRipper or Xeons instead?

Xeons CPUs that support over 44 lanes are more expensive need much more expensive ECC RAM, I guess.