Mismatched Memory and Single DIMMs

[d3athsd00r]

This has always been a topic that confused me and I've read different opinions everywhere I look.

 

I currently have 2x2GB RAM in my Virtualization Server with 9-9-9-24 Timings and 1.8V.

 

I need significantly more RAM in it but I'm trying to stay on a budget. I can get either 2x4GB of RAM now (its a microATX with 2 slots) and have 8GB, or I can get 1x8GB (for about the same price) and have 8GB and eventually get another 8GB.

 

I know that if I only have 1 stick then I lose the whole Double Data Rate attribute of DDR RAM, but would that be a significant performance hit?

Also, would it be advisable to put one of the other 2GB in with the 8GB if they are completely different timings/voltages or would that just be too unstable?

[sword_fish]

I know that if I only have 1 stick then I lose the whole Double Data Rate attribute of DDR RAM, but would that be a significant performance hit?

Also, would it be advisable to put one of the other 2GB in with the 8GB if they are completely different timings/voltages or would that just be too unstable?

 

you're trying to say double channel mode? correct me if i'm wrong but what i saw on wiki; DDR should not be confused with dual channel, in which each memory channel accesses two RAM modules simultaneously. The two technologies are independent of each other and many motherboards use both, by using DDR memory in a dual channel configuration.

 

and i would not mix two modules with different running specs (timings/voltages etc..), though there might be a way to make it possible...idk

[IVIYTH0S]

Yeah you'd only lose dual channel (not sure if it'd really make a huge real life performance hit that'd overshadow the benefits of the added memory...)

 

Why not get two more 2GB sticks, even though they aren't as good a deal per GB.

[d3athsd00r]

Ok, so I've been missunderstanding RAM for the past like 3 years. I thought that dual channel was what enabled the DDR attribute.

And I would have just added similar RAM, but I only have two DIMMS on my uATX. ;'(

[d3athsd00r]

So newegg is having a shellshocker on some 8GB Crucial, that I'm thinking about picking up.

[wevsspot]

Motherboards that offer dual channel, triple channel or quad channel memory support are independent of DDR memory (except for form factor, speed, timings, voltages etc.).  DDR=Double Data Rate.  Dual channel, triple channel and quad channel motherboards refer to the number of independent memory lanes that can be used for data transmission - i.e. reading, writing, copying.

 

Before making a decision on whether to purchase a 2x4Gb kit or a single 8Gb stick, make sure and determine the maximum memory support and speed of your motherboard.  A virtualization server will benefit from memory capacity, so if it were me (and the motherboard supports 16Gb of memory), I'd grab one 8Gb stick right now and add another later.

 

In your application you'll never know the difference between single channel and dual channel mode so it is ok for a short term fix to go with the single 8Gb stick.

[d3athsd00r]

It supports 16GB dual channel, so I'm thinking 8 now and 8 later will be my best bet.

[wevsspot]

That's exactly what I would do  

 

When you add your second module do your best to get the same brand, model, speed, timing, voltage as the first module to help minimize any compatibility issues.

[ty2010]

To run dual channel they have to be in specific slots as well, which slots exactly depends on the board. Some have to fill 0 and 2 first, others slots 1 and 3. You've likely been running single channel all along.

[wevsspot]

OP only has two DIMM slots on his motherboard.

[ty2010]

OP only has two DIMM slots on his motherboard.

That simplifies things immensely. Set to the looser timings and go, usually the only time issues are going to crop up is when trying to OC.