quick question about ddr ram

No there's different kinds of DDR sticks, and they've got different pins / keys on them.

There's DDR, DDR 2, 3 and now DDR 4. None of them are compatible with each other

And if it's a laptop thats completely different. Thats SODIMM ram/memory

And also, before you change the ram, make sure it can support 2x2 sticks of ram. Depending on how old the PC is. Otherwise it wont work or turn on.

If your PC is old, I dont think it'll support ECC ram

Whats the brand/model of this computer?

In addition to different RAM versions (DDR/DDR2/DDR3/DDR4), there is also RAM speed

DDR: 266/333/400
DDR2: 533/667/800
DDR3: 1066/1333/1600/1866 and so on
DDR4: 2133/2400/2666 and so on

Not all Memory speeds work with all motherboards. For instance, some DDR3 motherboards do not work with RAM speeds higher than 1333. Your system specifications should say what RAM is compatible with your system.

-Wolf sends

Whats the model?? Because XP cant use 4 GB of ram since its 32 bit. It'll only see 3.25 - 3.5 GB of 4 GB.

Thats if the motherboard supports that much ram

There is DDR, DDR2, DDR3, and now DDR4.

Most motherboards we use require DDR3 at this point. Nearly all of them.

DDR4 is just coming online, and starting with the next CPU release from Intel, DDR4 will be used. DDR and DDR2 are older, and only seen on very old motherboards now.

You cannot mix one kind of DDR with another. If your motherboard supports DDR3, them DDR3 is the only memory that can be used.

There are now a few types of DDR3. If you have a newer motherboard with UEFI BIOS, then all of these DDR3 memories will work fine. But if you have a pre-UEFI BIOS motherboard, some of the new high density DDR3 sticks will not work with them, and some of the newest PnP DDR3 memory sticks will also not work with them.

The solution is to look at the web page of the company that makes the motherboard you want to buy memory for. On the page they have for that motherboard will be a support link. Clicking on that link brings you to a page where you will see links to the supported CPU list, and the QVL (Qualified Vendor List), or fancy way of saying Tested and Approved Memory listing. Open the QVL list, and find a match from the product number at a dealer, and then buy that exact kit. If you want to be 100% certain that the memory will work with your motherboard, the model number of the kit must match that listed exactly. Also pay attention on that list to the speed of the memory kit... 1866 is pretty much the fastest memory you want. Also pay attention to the capacity of the kit. Always buy a kit of 2 sticks of memory. If you want 8GB total, buy a kit of 2 x 4GB memory. If you want 16GB, buy a kit of 2 x 8GB memory. It is harder for 4 sticks of memory to work at tight memory settings than with 2 sticks. And never just buy a single stick. All of these computers have dual channel memory controllers. You want to keep both channels loaded with a stick of memory.

And finally, make sure you buy a kit of 2 sticks and not just 2 single sticks. The kits have had the 2 sticks of memory tested together to make sure the memory controller will be able to easily work with both sticks.

It sounds complicated, but its actually pretty simple in the end. You want 1600 or 1866 memory. There is not a dramatic difference between the two speeds. In addition to the memory speed, you want a low latency, or CL. For 1600 you probably want CL7 or CL8. On 1866 speed memory, look for CL8 or CL9. A lower CL number is faster. Sometimes the companies don't show latency as a CL number, instead they will show it as a 3 or 4 part number. So 9-11-11-28 would be a CL of 9. 7-9-8-24 would be CL7.

If you would like a more detailed explanation, Toms posted an article that explains things in more detail than I can go into here. I think reading it would help you understand what I have said better...

http://www.tomshardware.com/reviews/ddr-dram-faq,4154.html

Hope this helps you.

See messages below.

[strike]That is server memory. It has ECC. ECC is not supported on these motherboards. They are also referring to it only as DDR.... It also has 184 pins.

You need DDR3. DDR3 has 240 pins.

If you want memory, go to a place where they sell computer parts and get it there. That way you have a place to return defective memory to, you know you are getting memory for a PC and not for a server, and you can see the reviews from the people that have purchased the same memory before.
[/strike]
Also, do yourself a huge, huge favor, and get at least 8GB of memory in a 2 x 4GB kit. 4GB may work most of the time, but many, many people here will tell you a system with 8GB of memory runs much smoother.

To get an accurate answer you will need to tell us what motherboard that you have - for example Asus M5A99X (that's not what you have, but something similar will be printed on the motherboard). The motherboard determines what type of memory you can install and how much per memory slot.

If you have PC2700U currently installed, then you likely have an old server motherboard, and you are correct in stating that it is DDR (before they came out with DDR2, DDR3, and DDR4).

No. That memory will not work on any motherboard designed for consumer oriented CPU's.

It wont be DDR 3 if its an older system

Ok.. he says DDR... but unless he has a server based motherboard with requires ECC, that is not going to work for him.

We do need to know the brand and model of your motherboard.

Correct well the brand/model of this system. Then we can check, and see what it supports

After looking very closely at your photos, and comparing to the non-ECC memory you linked, I do believe that what you took photos of, and what was last linked would be compatible. It should be a drop in replacement.

Have him download and run CPU-Z.

The mainboard tab should show what motherboard is in use.

-Wolf sends

If he does that, have him post the picture on one of those free pic sites so we can see the CPU-Z output.