# Need help what does PC4 mean



## jaront2008

what does PC4 mean on ram and doesn't matter that it's different between types of ram


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## TwoCables

All I think you need to worry about is finding memory that you know is compatible with your motherboard, and we generally look at whether it's DDR, DDR2, DDR3 or DDR4 (I've never seen the "PC" thing matter at all). So, what do you have for a motherboard?


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## jaront2008

already have the computer built i just wanted to add more ram but newegg sold out of the type of ram i got

motherboard http://www.newegg.com/Product/Product.aspx?Item=N82E16813132260

ram i have http://www.newegg.com/Product/Product.aspx?Item=N82E16820211914


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## CynicalUnicorn

Naming scheme for the DIMM. I believe "DDR4" refers to the memory chips themselves while "PC4" refers to the DIMM, the memory stick you plug into the slot. For example, DDR4-3200 refers to a memory chip that runs at 3200MT/s (megatransfers per second) while PC4-25600 refers to a DIMM that transfers 25.6GB/s. The PC4-25600 DIMM uses a bunch of DDR4-3200 chips, however.

Realistically it's nothing to focus on. The vast majority of people use the DDR#-WXYZ format, even though it's technically incorrect, rather than the PC#-VWXYZ format. DDR4-2800 and PC4-22400 are more or less the same thing on a shopping site, and they only really differ in the engineering white papers.


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## jaront2008

so if i understand you the pc4 it's basically the same thing as the speed of the memory


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## CynicalUnicorn

Quote:


> Originally Posted by *jaront2008*
> 
> so if i understand you the pc4 it's basically the same thing as the speed of the memory


It's the memory bandwidth, yeah, rather than the transfer rate. But you can get from point A to point B pretty easily:

(64-bit bus) * (1 byte / 8 bits) * (megatransfers / second) = (megabytes / second)

Which reduces to a 1:8 ratio of transfer rate to bytes per second. Unit cancellation. Use it. Love it.


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## TwoCables

Quote:


> Originally Posted by *jaront2008*
> 
> so if i understand you the pc4 it's basically the same thing as the speed of the memory


All you need to do is find DDR4 memory that's as similar as possible to the memory you have now. Make sure all of the specs are the same and you *should* be good to go. Make sure the rated voltages are the same, and make sure the "timings" are the same too.

You don't have to worry about anything else. So, let's stop looking at this "PC4" thing and focus on what really matters. DDR4, the clock speed, the rated voltage, and the timings. Get the best memory you can and you should be all set.


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## ElexTech

*ElexTech*

DDR4 Speeds:

PC4-21300 (2666Mhz) - PC4-22400 (28000Mhz) PC4-19200 (2400Mhz) - PC4-24000 (3000MHz) - PC4-17000 (2133 MHZ) - PC4-25600 (3200MHz) - PC4-26400 (3300MHz)


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## ElexTech

DDR4 Speeds:​ PC4-21300 (2666Mhz) - PC4-22400 (28000Mhz) PC4-19200 (2400Mhz) - PC4-24000 (3000MHz) - PC4-17000 (2133 MHZ) - PC4-25600 (3200MHz) - PC4-26400 (3300MHz)​


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## OfficerZero

*what should i choose ??*

I have a laptop Hp 15-da0434tx , cpu speed is 2.4ghz{ddr4 ram} , should i choose pc-4 19200(2400mhz) or pc-4 21300(2666mhz) ?


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## GSKILL SUPPORT

The CPU can only support DDR4-2133, so that is the highest the system will run at.


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## JimSal

TwoCables said:


> All I think you need to worry about is finding memory that you know is compatible with your motherboard, and we generally look at whether it's DDR, DDR2, DDR3 or DDR4 (I've never seen the "PC" thing matter at all). So, what do you have for a motherboard?


I have an hp erica2 and I want to upgrade my ram how much mhz can my mobo use?


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## TwoCables

JimSal said:


> I have an hp erica2 and I want to upgrade my ram how much mhz can my mobo use?


3200MHz. Just so you can be sure I have the facts, I asked Google and the first result was the motherboard specifications for this computer:






HP Desktop PCs - motherboard specifications, Erica2 | HP® Customer Support


Specifications for the Erica2 motherboard.




support.hp.com





Expand "Memory upgrade information".


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