Doesn't every DDR4 motherboard support any DDR4 stick?

[euskalzabe]

Regardless of speed (faster memory on slower mobo will perform slower, obviously), doesn't the DDR4 specification precisely serve to guarantee that any DDR4 DIMM will work on any DDR4 motherboard???

I ask because I'm about to build a new Ryzen pc and I've never had this concern before. I bought this Patriot kit a couple weeks ago on a good discount and I'm now seeing all motherboards may not support it. Right now only the Asus Prime B350M-A has the Patriot kit in its supported memory list.

How is this possible? I've never even checked for "motherboard memory compatibility" in any of the many PCs I've built over the past 15 years and I have never had any problems. Have I just been getting lucky all these years? Did something change with DDR4 making selection more troublesome?

Now I'm slightly worried that the memory I bought will limit what motherboard I can buy.

 

[DrLobotomy]

It will probably work. I like Patriot RAM.

You buy RAM to match the board, not the board to match the RAM, usually.

Update the BIOS and I would imagine you will have no problems.

 

[euskalzabe]

That's what I think, that it'll probably work, but my confusion remains. Isn't the point of DDR specification precisely to guarantee that any reputable DDR4 DIMM will work on a DDR4 motherboard? How can it be explained that it "might" not work?

Point is, you shouldn't need the motherboard manufacturer to tell you if a DDR stick works on their board or not. If it supports DDR4, it should support all DDR4 sticks. OC speeds, sure, that may run into problems, but just running the DDR stick should never be a problem. That's why the DDR specification exists. No?

I've never even thought of this, so I want to know if this is something I should start checking in the future. I don't really care about what motherboard to buy, as I only need to place the CPU, 1 GPU, 2 sticks of DDR and 3 drives. I don't overclock, so any simple mobo usually does the trick. So far I've never had a problem with memory, but I'm now wondering if this compatibility stuff is now "a thing" or people are just blowing any potential "incompatibility" it out of proportion.

 

[FrgMstr]

There is a reason there are specifications, but there are also reasons for certification as well. In a world of nearly endless mix and match vendors in PC, all things are not going to work all the time.

 

[DrLobotomy]

That's what I think, that it'll probably work, but my confusion remains. Isn't the point of DDR specification precisely to guarantee that any reputable DDR4 DIMM will work on a DDR4 motherboard? How can it be explained that it "might" not work?

Point is, you shouldn't need the motherboard manufacturer to tell you if a DDR stick works on their board or not. If it supports DDR4, it should support all DDR4 sticks. OC speeds, sure, that may run into problems, but just running the DDR stick should never be a problem. That's why the DDR specification exists. No?

I've never even thought of this, so I want to know if this is something I should start checking in the future. I don't really care about what motherboard to buy, as I only need to place the CPU, 1 GPU, 2 sticks of DDR and 3 drives. I don't overclock, so any simple mobo usually does the trick. So far I've never had a problem with memory, but I'm now wondering if this compatibility stuff is now "a thing" or people are just blowing any potential "incompatibility" it out of proportion.

Money and logic don't always go hand in hand.

I would imagine a low level hardware programmer could answer this more intelligently, But I would imagine it has something to do with the fact some boards have higher quality circuitry to allow a more robust RAM type. For overclocking etc.

 

[FrgMstr]

I've contacted Patriot, I'll post when I hear back on what they have to say. If one doesn't do any "demanding" OC stuff with memory/board, I see no reason why a reputable memory/mobo brand following the certification should not just work. It's also implausible that I've been getting lucky with 10 PCs built in the past 15 years. Something's iffy here and I intend to find out. Meanwhile, I hope AM4 memory support increases by the time Ryzen 5 is released.

There is something "iffy" here. LOL! OK. That said, I would not expect every DDR4 stick on the planet to work with every DDR4 motherboard, especially on a brand new platform. A stick of DDR4 built around Intel a year ago might work on AMD's just released platform, but don't think it is guaranteed.

 

[drescherjm]

I would expect JEDEC standard dimms to work at the standard speed (and standard timings) however these days a lot of memory is overclocked .

 

[euskalzabe]

Ended up getting an i5 7500 and Asus B250M-A - which supports the Patriot memory at 3200 OC and also works in quad channel if I want to add another 8gb in the future. I wanted to go with Ryzen (I'm not happy about rewarding Intel's laziness), but I guess it'll be next time.

If anything I'm being quite democratic: Phenom II X4 955 > i5 2500 > FX 6300 > i5 7500. Next, Zen 3?

 

[bluesynk]

Memory compatibility charts have been a thing from way back. like p4 ddr2 days at least in my memory. I tend to find them later, after i have everything and start downloading drivers. one of these days i might remember to check. I had a set of mushkin ram that didnt get on many lists but moved from pc to pc fine. and wasent there some kind of intel vs amd ddr3 differences?

 

[Robergal]

Memory compatibility charts have been a thing from way back. like p4 ddr2 days at least in my memory. I tend to find them later, after i have everything and start downloading drivers. one of these days i might remember to check. I had a set of mushkin ram that didnt get on many lists but moved from pc to pc fine. and wasent there some kind of intel vs amd ddr3 differences?

Been building since we had 1 meg sticks at 50 dollars a meg!
Not all memory is the same even within specs. Different memory chips from different MFG same with the PCB and the traces.
Having said that it been a long time since I had memory fail! Mine not PC .
Purchased 2 sticks of GEIL PC 2400 and tried it in two different X370 Boards no post at all. I did everything but change the ram not believing it was bad. Yes I tried 1 stick in all 4 slots.
Bought some memory locally G.Skill fury 2166 at 14 cas Cost me way more than it should have but it works!
Just got my g.Skill trident 3200 at cas 14. Cost was the same.
Both work wonderfully and the 3200 is supported on my Asus Prime x370 with the 504 bios.

 

[Dan_D]

The short answer is "yes and no."

The longer answer is well.....a lot longer. As long a memory module conforms to JEDEC specification then it should technically work at JEDEC approved speeds on any motherboard supporting that memory standard. This is the theory anyway. The reality is a bit more complicated. Memory modules designed for use in enthusiast oriented motherboards and systems also support XMP 1.x / 2.0 profiles. I've only ever had trouble making memory work on motherboards at JEDEC speeds once or twice in the last ten years or so that I can recall. It doesn't happen very often. At speeds above the JEDEC standards is another story.

I frequently change the modules I use in reviews because newer platforms supporting the same memory interface don't always work well with the modules I have on hand. The reality is that there are a lot of sub-timings that most people, including enthusiasts ignore. It's one thing to build a piece of hardware to match certain specs but things get messy when software or firmware of any kind is involved. In this case, memory modules have a BIOS of sorts onboard called an SPD EEPROM. The SPD is a feature called "Serial Presence Detect." This has code on it that the BIOS / UEFI reads to determine how to set those values in the UEFI so that the system can use them correctly. Issues can arise from SPD implementation. The SPD also stores EPP and XMP data in addition to the JEDEC approved SPD timing tables. Compatibility problems can arise when the motherboard doesn't detect the SPD timings or XMP timings correctly. This is more common than you think. Motherboard manufacturers may elect to read timings and use a different value anyway. This is either due to an error in the UEFI code, the SPD lookup tables or a conscious decision by the motherboard manufacturer to set memory values a certain way.

Its one of the ways motherboard manufacturers can cheat in benchmarks. Another common way is to run the baseclock slightly over the Intel spec limit to gain a few MHz of CPU and memory clock speed over their competitors. This isn't as big an issue as it once was but it does still happen. I've seen many motherboards that detect timings that are way tighter than what the memory manufacturer spec'ed the RAM for. In some but not all of these cases, the SPD viewer (assuming the board has one) may show more relaxed timings in the JEDEC and XMP profiles. This tells me that the RAM's SPD tables are being read correctly but tighter values are used anyway. This is likely the cause of trouble when we report having to tune memory by hand on some motherboards. Again, it doesn't happen a lot right now but it was VERY common with Z170 and X99 motherboards. To this day those platforms are hit and miss with SPD and XMP profiles. My own motherboard doesn't work beyond JEDEC specs with the XMP profiles on three different RAM kits I've used with it. I can dial in the same settings manually and it works telling me that there is something off in the sub-timings that's causing the issue.

Some motherboard brands have more glaring issues with compatibility than others. Sometimes, compatibility comes down to the memory manufacturers. There is a reason I avoid Mushkin or G.Skill RAM. I've had nothing but problems with those brands on a variety of motherboards and systems. In truth, you take a risk using RAM on any motherboard that's not on that motherboard's QVL list. The QVL process for motherboards essentially involves testing those modules on the motherboard in question, and ensuring that the detected and chosen values in the UEFI allow for stable operation at supported speeds.

But wait there's more! If you thought that was the end of the compatibility struggle you haven't heard the whole story. Since AMD and Intel both started using integrated memory controllers things have become even more difficult on the compatibility front. When using memory speeds outside of JEDEC specs, some IMC's are weaker or stronger than others. My test 5960X can achieve clock speeds of 4.5GHz with memory speeds at DDR3 3000MHz. My personally owned chip can't do more than 4.5GHz at DDR4 2666MHz. This is on the same exact motherboards mind you. Meanwhile, the Broadwell-E chips I've tested were marginally better, and could hit speeds of DDR4 3200MHz with more regularity and less drama. Rarely have I ever seen XMP work properly on X99 motherboards. I've had bad luck with Corsair, Patriot and Crucial memory on X99 and Z170. Its possible other brands are better at XMP compatibility with these chipsets but I haven't used them recently. I've seen better results out of Z270 and Kaby Lake than anything else newer than X79 or Z97. Most Kaby Lake CPU's I've seen can do DDR4 3600MHz at virtually any clock speed all day long. XMP compatibility is still somewhat hit and miss but the hit rate is many times greater than it was on the older platforms.

EDIT: (Forgot to include this little gem.)

I almost forgot, some modules have more than one XMP profile. As you can imagine that complicates matters even more. This should be fine assuming both profiles actually contain clock speeds, voltages and timings the modules can actually use. If you thought this would always be the case you'd be wrong. This is very common with Corsair memory. Corsair in its infinite Wisdom sometimes sees fit to include profiles for RAM that go beyond what the RAM is actually rated for. It's more common on pre-production samples they sometimes send us but my retail purchased 32GB (4x8GB) Corsair Vengeance LPX DDR4 2666MHz ram has a 2800MHz profile on it. Even if it could clock that high, its a no go on X99 motherboards that prefer a 125MHz strap setting. I don't know if any other manufacturers do this, but its common with Corsair RAM which is of course, extremely common. When you have two profiles the motherboard has to choose which profile it will use. For whatever reason, the board may default to the second XMP profile.

Think I'm done? Guess again! Memory compatibility, like CPU stability while overclocking also has a lot to do with the motherboard and how its designed. Motherboards with fewer PCB layers do not support clock speeds as high as those with thicker PCB's do. Electrical design makes a difference too. While most motherboards now use a single phase that's been doubled, the quality of the doubling effect and VRM's can still vary. By the same token I've seen motherboards with an extra phase for memory and they weren't any better than more contemporary designs. The topology of the memory trace paths also comes into play. This is why some motherboards can clock RAM higher than others. All the UEFI tricks or manual settings in the world won't matter if a given motherboard simply can't sustain the current and signal integrity required to do so. Chipsets have a lot to do with it as I alluded to earlier. Not because of something magic per se in the chipset but because of how they interface with the RAM. Some chipsets like X99 have to use strap settings based on the base clock of the motherboard. You have to keep the base clock within certain ranges or shit goes sideways real fast. Some hardware combinations may or may not behave with a particular module set, CPU and certain memory dividers. With Z170 and Z270 things are easier because the base clock and memory clocks are fully independent of one another.

Still awake? Probably not but there's more. Things even get worse when you start talking about loading the IMC on the CPU with more modules. This simply complicates things even further. In addition to subtle variations between using multiple memory kits (even from the same manufacturer, from the same model, or even the same batch) you can run into additional problems. The IMC on a Haswell-E or Broadwell-E CPU may not take kindly to being loaded with all 8 DIMMs. I've had very little success mixing and matching kits. If you want to max out an X99 system, you really want to buy 8x 16GB chips that are all part of the same kit. Such kits are expensive but they do exist.

One more thing and I think I'm done: You can still have issues due to memory manufacturer's binning practices. If a given kit is at the edge of what its rated for, it may not behave when clocked at those speeds in specific systems. Thermal tolerances, voltage variations and other factors come into play when you are at the edge like that. As a result of a crap ton of variables, memory compatibility and thus your results with different modules will vary.

In closing, theoretically any module should be compatible with any motherboard. This is only more or less possible or even guaranteed at JEDEC approved specifications and speeds. Going beyond that it's a clusterfuck and almost a total crap shoot from the consumer's perspective.

 

[illram]

And Dan_D just dropped the mic on this thread.

 

[Dan_D]

That reminds me. I forgot to add one more thing so I edited the post and noted where the new information is. Very shortly, I'll be knee deep in the memory compatibility shenanigans of Ryzen. We'll see how that goes. I'm hoping some of the BIOS updates out there will make my experience a bit less painful.

 

[Cyberbeing]

There have also been cases in the past where certain memory rank (single vs dual) and chip layout configurations were unsupported by a motherboard bios, though the last time I ran into something like that personally was with a DDR1 server board. Probably less common nowadays, but if you ever do notice all RAM on a QVL list using identical chip configurations and/or IC vendor, I'd be very wary about buying anything drastically different.

 

[Nenu]

Doesn't every DDR4 motherboard support any DDR4 stick?

No

 

[Ultima99]

The short answer is "yes and no."

The longer answer is well.....a lot longer. As long a memory module conforms to JEDEC specification then it should technically work at JEDEC approved speeds on any motherboard supporting that memory standard. This is the theory anyway. The reality is a bit more complicated. Memory modules designed for use in enthusiast oriented motherboards and systems also support XMP 1.x / 2.0 profiles. I've only ever had trouble making memory work on motherboards at JEDEC speeds once or twice in the last ten years or so that I can recall. It doesn't happen very often. At speeds above the JEDEC standards is another story.

I frequently change the modules I use in reviews because newer platforms supporting the same memory interface don't always work well with the modules I have on hand. The reality is that there are a lot of sub-timings that most people, including enthusiasts ignore. It's one thing to build a piece of hardware to match certain specs but things get messy when software or firmware of any kind is involved. In this case, memory modules have a BIOS of sorts onboard called an SPD EEPROM. The SPD is a feature called "Serial Presence Detect." This has code on it that the BIOS / UEFI reads to determine how to set those values in the UEFI so that the system can use them correctly. Issues can arise from SPD implementation. The SPD also stores EPP and XMP data in addition to the JEDEC approved SPD timing tables. Compatibility problems can arise when the motherboard doesn't detect the SPD timings or XMP timings correctly. This is more common than you think. Motherboard manufacturers may elect to read timings and use a different value anyway. This is either due to an error in the UEFI code, the SPD lookup tables or a conscious decision by the motherboard manufacturer to set memory values a certain way.

Its one of the ways motherboard manufacturers can cheat in benchmarks. Another common way is to run the baseclock slightly over the Intel spec limit to gain a few MHz of CPU and memory clock speed over their competitors. This isn't as big an issue as it once was but it does still happen. I've seen many motherboards that detect timings that are way tighter than what the memory manufacturer spec'ed the RAM for. In some but not all of these cases, the SPD viewer (assuming the board has one) may show more relaxed timings in the JEDEC and XMP profiles. This tells me that the RAM's SPD tables are being read correctly but tighter values are used anyway. This is likely the cause of trouble when we report having to tune memory by hand on some motherboards. Again, it doesn't happen a lot right now but it was VERY common with Z170 and X99 motherboards. To this day those platforms are hit and miss with SPD and XMP profiles. My own motherboard doesn't work beyond JEDEC specs with the XMP profiles on three different RAM kits I've used with it. I can dial in the same settings manually and it works telling me that there is something off in the sub-timings that's causing the issue.

Some motherboard brands have more glaring issues with compatibility than others. Sometimes, compatibility comes down to the memory manufacturers. There is a reason I avoid Mushkin or G.Skill RAM. I've had nothing but problems with those brands on a variety of motherboards and systems. In truth, you take a risk using RAM on any motherboard that's not on that motherboard's QVL list. The QVL process for motherboards essentially involves testing those modules on the motherboard in question, and ensuring that the detected and chosen values in the UEFI allow for stable operation at supported speeds.

But wait there's more! If you thought that was the end of the compatibility struggle you haven't heard the whole story. Since AMD and Intel both started using integrated memory controllers things have become even more difficult on the compatibility front. When using memory speeds outside of JEDEC specs, some IMC's are weaker or stronger than others. My test 5960X can achieve clock speeds of 4.5GHz with memory speeds at DDR3 3000MHz. My personally owned chip can't do more than 4.5GHz at DDR4 2666MHz. This is on the same exact motherboards mind you. Meanwhile, the Broadwell-E chips I've tested were marginally better, and could hit speeds of DDR4 3200MHz with more regularity and less drama. Rarely have I ever seen XMP work properly on X99 motherboards. I've had bad luck with Corsair, Patriot and Crucial memory on X99 and Z170. Its possible other brands are better at XMP compatibility with these chipsets but I haven't used them recently. I've seen better results out of Z270 and Kaby Lake than anything else newer than X79 or Z97. Most Kaby Lake CPU's I've seen can do DDR4 3600MHz at virtually any clock speed all day long. XMP compatibility is still somewhat hit and miss but the hit rate is many times greater than it was on the older platforms.

EDIT: (Forgot to include this little gem.)

I almost forgot, some modules have more than one XMP profile. As you can imagine that complicates matters even more. This should be fine assuming both profiles actually contain clock speeds, voltages and timings the modules can actually use. If you thought this would always be the case you'd be wrong. This is very common with Corsair memory. Corsair in its infinite Wisdom sometimes sees fit to include profiles for RAM that go beyond what the RAM is actually rated for. It's more common on pre-production samples they sometimes send us but my retail purchased 32GB (4x8GB) Corsair Vengeance LPX DDR4 2666MHz ram has a 2800MHz profile on it. Even if it could clock that high, its a no go on X99 motherboards that prefer a 125MHz strap setting. I don't know if any other manufacturers do this, but its common with Corsair RAM which is of course, extremely common. When you have two profiles the motherboard has to choose which profile it will use. For whatever reason, the board may default to the second XMP profile.

Think I'm done? Guess again! Memory compatibility, like CPU stability while overclocking also has a lot to do with the motherboard and how its designed. Motherboards with fewer PCB layers do not support clock speeds as high as those with thicker PCB's do. Electrical design makes a difference too. While most motherboards now use a single phase that's been doubled, the quality of the doubling effect and VRM's can still vary. By the same token I've seen motherboards with an extra phase for memory and they weren't any better than more contemporary designs. The topology of the memory trace paths also comes into play. This is why some motherboards can clock RAM higher than others. All the UEFI tricks or manual settings in the world won't matter if a given motherboard simply can't sustain the current and signal integrity required to do so. Chipsets have a lot to do with it as I alluded to earlier. Not because of something magic per se in the chipset but because of how they interface with the RAM. Some chipsets like X99 have to use strap settings based on the base clock of the motherboard. You have to keep the base clock within certain ranges or shit goes sideways real fast. Some hardware combinations may or may not behave with a particular module set, CPU and certain memory dividers. With Z170 and Z270 things are easier because the base clock and memory clocks are fully independent of one another.

Still awake? Probably not but there's more. Things even get worse when you start talking about loading the IMC on the CPU with more modules. This simply complicates things even further. In addition to subtle variations between using multiple memory kits (even from the same manufacturer, from the same model, or even the same batch) you can run into additional problems. The IMC on a Haswell-E or Broadwell-E CPU may not take kindly to being loaded with all 8 DIMMs. I've had very little success mixing and matching kits. If you want to max out an X99 system, you really want to buy 8x 16GB chips that are all part of the same kit. Such kits are expensive but they do exist.

One more thing and I think I'm done: You can still have issues due to memory manufacturer's binning practices. If a given kit is at the edge of what its rated for, it may not behave when clocked at those speeds in specific systems. Thermal tolerances, voltage variations and other factors come into play when you are at the edge like that. As a result of a crap ton of variables, memory compatibility and thus your results with different modules will vary.

In closing, theoretically any module should be compatible with any motherboard. This is only more or less possible or even guaranteed at JEDEC approved specifications and speeds. Going beyond that it's a clusterfuck and almost a total crap shoot from the consumer's perspective.

Note to Kyle - Make sure you hang onto this guy.

 

[Dan_D]

There have also been cases in the past where certain memory rank (single vs dual) and chip layout configurations were unsupported by a motherboard bios, though the last time I ran into something like that personally was with a DDR1 server board. Probably less common nowadays, but if you ever do notice all RAM on a QVL list using identical chip configurations and/or IC vendor, I'd be very wary about buying anything drastically different.

I didn't get into that because it's been years since I've seen a single rank memory module. Evidently, they still exist. Typically this was something I saw a lot with server hardware in the past. I haven't physically had to lay my hands on server hardware in a good while so that could be why I never see that. Single rank modules have never been all that common on consumer hardware. The only times I ever saw it in the past where when a system was put together using the cheapest of parts by an OEM. The types of modules enthusiasts buy are never single rank.