I need to know about ram compatability

[Ns2222]

If you have 4gbs of ram and you add another stick of 4gbs I know I has to be the same ddr but what about memory speed and manufacter can I just stick a second stick of ddr3 4gb ram into it and I have 8 I just want to make sure

 

[10tacle]

The rule of thumb for memory is that they are only guaranteed to work together if purchased in a kit (2 or 4 sticks). Those are tested at the factory and are guaranteed to work together. Even the same make and model of RAM may not work if bought separately. The reasons are complex, but the simple answers are that manufacturing tolerances of the silicon can variate as well as manufacturers may change memory module vendors from one manufacturing cycle to the next.

So you can try it, but there's no guarantee it will work. Regarding different speed, the slowest RAM will be the speed at which the faster RAM runs. So for example if you put a DDR3 1833 stick with a 1600 stick, your PC will run your memory at 1600.

 

[aquielisunari]

If you have 4gbs of ram and you add another stick of 4gbs I know I has to be the same ddr but what about memory speed and manufacter can I just stick a second stick of ddr3 4gb ram into it and I have 8 I just want to make sure

Let's assume you have DDR3 1333MHz(aka PC 10666) CAS 9 1.5V

Your module needs to be DDR3 as well. It needs to have an identical speed(1333MHz). The latency(timings or CAS latency) 9 needs to be identical. And the voltage(1.5V) also needs to be identical. The size should be the same but that is not required although it is strongly recommended. You can pair a 2GB module with an 8GB module as long as the motherboard supports 8GB modules(aka sticks). You can also pair different brands but that isn't recommended either.

Let's assume someone did that. They purchased an identical module. Same brand too. IT DOESN'T WORK!!!!! I can take out the other module and it works fine. What the pickle!!!!!??? RAM modules are sold in kits too. Sam across the street purchased a 16GB(2x8) kit, left out the old module and his works fine. Just because the module is identical doesn't guarantee compatibility. Only RAM modules sold in kits are guaranteed to be compatible.

The motherboard also has a say in this. Let's say Sam installed his RAM modules in the first 2 RAM(aka DIMM) slots. It doesn't work!!!? He reads his manual. He was supposed to install the modules in slots 1(closest to the CPU) and 3(skip one slot). He did that and everything s fine now.

Touch something metal prior to touching the RAM or opening your case. RAM modules are susceptible to an ESD(electrostatic discharge). Every touch a door and get a wee little shock or rubbed a balloon on your head and it sticks? RAM hates static electricity.

I will learn how to sepll one of these days!!!

 

[elbert]

If you have 4gbs of ram and you add another stick of 4gbs I know I has to be the same ddr but what about memory speed and manufacter can I just stick a second stick of ddr3 4gb ram into it and I have 8 I just want to make sure

There is a RAM spec called Jedec with the most important part is voltage. DDR3 Jedec standard is 1.5v so long as your DDR3 RAM is 1.5v your other RAM should work with the new stick. The RAM willl work at the slower RAM's speed. This is single channel.

On getting dual channel you can try to match your new RAM to your old but more liklely than not its not going to work in dual channel. If you want dual channel do yourself a favor and get a kit.

 

[JackNaylorPE]

This is a simple thing really.... and confining the discussion to dual channel ? 2 sticks.

1. Dual channel memory is designed to work in pairs ..... that means ya supposed to by a package of 2.

2. RAM is tested at the factory to make sure they work **in pairs**. What likely happens to RAM that doesn't pass the test ? It's sold as single sticks. So when buying single sticks, there's a fair likelihood that the stick had trouble "playing with others".

3. If you don't buy them together you have no guarantee that it will work with any other stick.

4. if you decide to enter the crapshoot that is adding RAM, you want to try and match as many things as possible including manufacturer, model line, DDR type (essential), series, version number, timings and module supplier. Manufacturer's often switch suppliers over time and may use one supplier for version 2.62 and another for version 3.13

5. The lower the speed and higher the timing, the better chance you have of getting the pair to work. The higher the speed, the lower the timing the lower the yields will be for that model and the harder.

6. The MoBo must be able to support the speeds and timings.

7. The JEDEC spec is for the most part irrelevant because most RAM purchased ... and I am talking in excess of 95% ... is not JEDEC compliant, at least not at the advertised speeds listed on the package. It will have JEDEC compliant settings programmed into the SPD, but the number on the package 98% of the time will be the XMP rating. If you bought a set of DDR3-1600 way back when, that number on the package and the number used in the advertising is the XMP rating. XMP is an Intel standard which, by definition is overclocked and therefore exceeds the JEDEC spec ...

https://www.intel.com/content/www/us/en/gaming/extreme-memory-profile-xmp.html

I have seen 100s of posts claiming that if ya exceed the JEDEC voltage, your system is toast. Intel publishes a huge list or RAM kits that a certified compatible" which are well in excess of JEDEC voltages. No MoBo manufacturer has ever had an issue with listed XMP required voltages when their literature states it supports DDR speeds that require those voltages.

At the time when JEDEC covered up to 1333 @ 1.5 volts, the XMP or advertised rating was 1600 @ 1.65. Over time, JEDEC spec was revised to add faster speeds but again, most of the enthusiast / gaming community has never installed RAM using the JEDEC settings. Back then the appropriate voltage for XMP was 1.65 for these sticks. Over time we saw JEDEC adopt faster speeds and we saw production line improvements deliver lower voltages (down to 1.25) but even in DDR3's waning days.... 1.65 was common for 2133 and up.

Even now we are seeing the same thing with DDR4 about anything over the JEDEC 1/2 is oooh ooh scary scary ....and yet, Intel still has much higher voltages on its certified compatible list.

http://www.legitreviews.com/what-is-the-safe-voltage-range-for-ddr4-memory-overclocking_150115

So while JEDEC goes ony up to 1.2v Intel says:

“1.5v is the absolute max we allow for XMP certifications. However, good DDR4 memory will run at 1.35v up to 3200. Technically, no “safe” (guaranteed) OC over-voltage but 1.35v or lower is best.” – Intel

So, JEDEC is only going to be relevant if you bought some very inexpensive RAM that has no XMP (Intel) or AMP AMD) rating.
That RAM in the CPUz image above was sold as DDR3-2400 on the package....to get that speed you will need to use 1.65 volts. It's been running at 1.71 volts for 3+ years.

The long and short of it is, you want to match what you have now whether it be JEDEC or XMP ratings and settings. If you find yourself with a stick of XMP rated DDR3-1600 RAM @ 1.65 volts and then a later model with JEDEC rated 1600 at 1.5 volts, it would not be worthwhile to attempt to make that pairing. That being said, if I had a 2nd stick for free, I'd try and get bit to work at the lowest common settings.... But I wouldn't invest in paying for one. I'd sell it and buy a pair.

 

[elbert]

Here is an easier answer.
https://www.howtogeek.com/217849/can-i-use-two-types-of-ddr3-ram-with-the-same-motherboard/