Memory Voltage

[Cathal]

Hello everyone

I've lately been looking at RAM and noticed varying voltages on various sticks (for example some DDR4 memory has a voltage of 1,2 and other 1,35, to name an example). I'm curious with regards to the effect this has on performance, what the safe and expected voltages are and any other clear information on this topic. I wouldn't mind if you could dumb things down a bit, since most knowledge I have is basically self-taught.

Thanks!

[Midnight Fawn]

This may answer some of your questions.. :)

http://www.techspot.com/news/58832-tech-primer-ddr4-memory.html

[Cathal]

引用自 Scottish Tablet：

This may answer some of your questions.. :)

http://www.techspot.com/news/58832-tech-primer-ddr4-memory.html

Thanks!

Basically what I got from that is "Lower voltage components simply run cooler than their higher voltage counterparts and are generally more reliable. There are of course exceptions to this, but as a general rule of thumb I have found it to be fairly accurate."

Also that each iteration of DDR went lower with their voltage. 2 had around 2V, 3 had 1,5V and 4 generally has 1,2V.

[Rumpelcrutchskin]

1.35V DDR4 RAM is high Mhz overclocking RAM for high end rigs used with overclocking capable motherboards like Z270 and K-version CPUs.
1.2V DDR4 RAM is usually for budget builds that you dont overclock, like B250 boards for locked core Kaby Lake CPUs that can use up to 2400 Mhz DDR4 RAM or previous generation B150 that can use 2133 Mhz DDR4 RAM.

[Big Boom Boom]

1.35V DDR4 are Overclocked, they are higher than standard 2133/2400Mhz speed. In fact, they tend to be much more reliable as they are made of better quality to allow the overclocking in the first place, though they will be hotter of course.

[Cathal]

引用自 Rumpelcrutchskin：

1.35V DDR4 RAM is high Mhz overclocking RAM for high end rigs used with overclocking capable motherboards like Z270 and K-version CPUs.
1.2V DDR4 RAM is usually for budget builds that you dont overclock, like B250 boards for locked core Kaby Lake CPUs that can use up to 2400 Mhz DDR4 RAM or previous generation B150 that can use 2133 Mhz DDR4 RAM.

So in your opinion, it'd be better to get the higher voltage RAM if one already owns a Z170/Z270 motherboard?

引用自 Big Boom Boom：

1.35V DDR4 are Overclocked, they are higher than standard 2133/2400Mhz speed. In fact, they tend to be much more reliable as they are made of better quality to allow the overclocking in the first place, though they will be hotter of course.

Would you say the heat differs significantly or not, since higher end RAM tends to have heatspreaders as well?

[Rumpelcrutchskin]

引用自 Cathal：

引用自 Rumpelcrutchskin：

1.35V DDR4 RAM is high Mhz overclocking RAM for high end rigs used with overclocking capable motherboards like Z270 and K-version CPUs.
1.2V DDR4 RAM is usually for budget builds that you dont overclock, like B250 boards for locked core Kaby Lake CPUs that can use up to 2400 Mhz DDR4 RAM or previous generation B150 that can use 2133 Mhz DDR4 RAM.

So in your opinion, it'd be better to get the higher voltage RAM if one already owns a Z170/Z270 motherboard?

Yeah if you had Z170 or Z270 motherboard then it's best to use 3000+ Mhz DDR4 RAM.
Check the motherboard info for what Mhz ranges it supports, this can vary between manufacturers and specific boards.
Also good idea to check the motherboard manufacturers homepage for RAM brands officially supported for this specific motherboard.

[Bad 💀 Motha]

1.2V is for non-OC RAM for cheaper boards (non Z170 / Z270)
around 2666 and slower. So at around 2666 or lower, the voltage in the RAM specs should be 1.2V; 1.35V is needed for higher end OC RAM like 2800+

[Cathal]

引用自 Bad-Motha：

1.2V is for non-OC RAM for cheaper boards (non Z170 / Z270)
around 2666 and slower. So at around 2666 or lower, the voltage in the RAM specs should be 1.2V; 1.35V is needed for higher end OC RAM like 2800+

So it solely influences the speeds of the RAM? Would you say it's worth the heat increase in a tower or is it pretty insignificant? Especially considering older RAM use to run a lot higher.

[Bad 💀 Motha]

RAM doesn't really get hot, period. I wouldn't be worried about RAM heat.
They really don't even need heat-spreaders on them. If anything those are more to protect the RAM.

Basically it comes down to; Higher speeds require more voltage.
Look at previous gens of RAM, same deal.

[Aliquis Freedom & Ethnopluralism]

引用自 Cathal：

引用自 Rumpelcrutchskin：

1.35V DDR4 RAM is high Mhz overclocking RAM for high end rigs used with overclocking capable motherboards like Z270 and K-version CPUs.
1.2V DDR4 RAM is usually for budget builds that you dont overclock, like B250 boards for locked core Kaby Lake CPUs that can use up to 2400 Mhz DDR4 RAM or previous generation B150 that can use 2133 Mhz DDR4 RAM.

So in your opinion, it'd be better to get the higher voltage RAM if one already owns a Z170/Z270 motherboard?

Back before when Intel added integrated memory controllers (which was part of what was called the north-bridge of the chipset before, by now I don't even know whatever an actual chipset is used or rather just a chip because some functionality has been brought into the processor, for some integrated processors you'll even see the name "system on a chip" for chips with even more integrated functionality) going with over-clockers RAM risked damaging the processor and lead to instability. Even now Kaby lake and Skylake provide actual support for DDR3L and there's motherboards with DDR3 slots around and you can stick a DDR3 memory module down there but they don't officially support DDR3 and likely you're pushing the design beyond it's designed for limits and risk damaging the components by using one.

Wikipedia doesn't seem very trustworthy for voltages:
For DDR2 the standard was 1.8 or 1.9 volt.
For DDR3 1.35 or 1.50 volt. JEDEC consider the maximum voltage for stability to be 1.575 volt and that they should be able to survive 1.8 volt though they don't have to function at that voltage.
The DDR3L specs supposedly is 1.35 volt and 1.50 volt too, I thought it was lower, newer Intel systems supposedly only operated at 1.35 volt and hence wasn't compatible with them regardless.
DDR3U (for Ultra Low Voltage) standard is 1.25 volt.
DDR4 voltages supposedly is 1.2-1.4 volt but mention 1.5-1.65 for DDR3, which you can see above doesn't match up with the claimed 1.35-1.50 on the Wikipedia entry for DDR3. So something doesn't add up.

I thought DDR3L was close to DDR4 voltages and that DDR3 sat higher and hence isn't compatible with those processors.

Anyway, back before if you ran higher voltages and indeed higher frequencies your stability and how long your products lasted could go down.

As such I don't necessarily buy into the claim that those products are of a higher quality. I know even back in E8400 era that the faster RAM could mean problems and that sticking with the standard was better. So it was with Skylake too and if you follow the news about Ryzen 7 .. well..
Faster is faster when it works though. And maybe the higher tiered products is better for that at-least.

The case is similar with Ryzen 7 too where supposedly the Ryzen 7 1700 is less "leaky" or whatever and the 1800X more so but work better at a higher clock frequency. I don't even know what that mean!! But possibly the Ryzen 7 1700 can run at lower voltages and use less power but not over-clock as well whereas the 1800X can handle more but also use more energy. Why the less leaky design isn't the superior one when you raise the volt and clock I don't know!

I also don't know if an OC RAM module can work just fine at standard voltages and speed or be superior to a more standard stick there or not. In the case of the Ryzen 7 claims maybe one could assume the 1700 was the "better" chip if less leaky(?, is that the word?) is an advantage assuming one ran with the default settings.

From my understanding of stability and safety of it as far as I understand it going with 1.2 volt and 2400 MHz RAM is most likely the best for stability, compatibility and maybe also longevity.
However for performance faster is better if you can can get a RAM to function at a higher frequency and voltage then performance will be better with that. So there's as far as I know a trade-off there. What happen with the OC RAM at standard settings I don't know. But if someone know feel free to tell me!! It would be appreciated.

Personally I would preferably find as fast RAM as possible which has been tested to be compatible and run that and hope it worked. If it didn't I would scale back the settings towards standard settings and hope it worked that way. Then again; if one look at the Ryzen 7 results where the higher clocked chip is a more leaky more voltage and power-demanding one then it could be the case that that is also true for the RAM chips and maybe these higher-frequency chips NEED higher voltage to perform well and will use more power even at lower settings. But hold up better to higher voltages and frequencies too. I'm nowhere near into the business of designing chips so I don't know how it works. But as said; I would appreciate to know :)

引用自 Rumpelcrutchskin：

引用自 Cathal：

So in your opinion, it'd be better to get the higher voltage RAM if one already owns a Z170/Z270 motherboard?

Yeah if you had Z170 or Z270 motherboard then it's best to use 3000+ Mhz DDR4 RAM.
Check the motherboard info for what Mhz ranges it supports, this can vary between manufacturers and specific boards.
Also good idea to check the motherboard manufacturers homepage for RAM brands officially supported for this specific motherboard.

My understanding is rather than 2133 or 2400 MHz is the best choice for those motherboards. One store here in Sweden which assemble builds for people only offered that service for setups with 2133 MHz RAM because of instability issues which could come from any other RAM (they unlikely want people sending their PCs back because it doesn't work well .. or run into troubles installing Windows on the PC builds because people had choosen very fast RAM which wasn't fully compatible.)
But as said, if one can get faster RAM then that has advantages too.

[Bad 💀 Motha]

Honestly, just stick to the lowest CAS DDR4 2400 and you'll be fine.