Mixing RAM on the GA-X58A-UD3R Motherboard

[angelonc]

Hey guys,

I just bought a 8GB (2x4gb) RAM kit (http://www.newegg.com/Product/Product.aspx?Item=N82E16820231416)

And I currently have another kit installed with 6GB total (3x2gb); (http://www.newegg.com/Product/Product.aspx?Item=N82E16820231185 <-- this is the only thing I could find with a matching part number, although I think it is incorrect)

I've never tried to mix RAM before, but I want to try to get as much memory out of these as possible, what do you all recommend?

I suspect I will have to at least sacrifice one of the older 2gb cards?

Some specs:

Windows 7 64bit
Intel Core i7 940 BloomField
Gigabyte X58A-UD3R Board
6GB (3x2GB modules) G.Skill RAM, part number F3-12800CL9-2GBNQ

Thanks!

 

[Xttony]

Well you can try to put the new ones in two same coloured slots. If the old cards and the new cards have different operating voltages then I don't really think it will work. It may work but you will end up with a crash sooner or later. If you still want to continue you can just clear bios settings by pressing the clear cmos key at the back of your motherboard and continue using it.

 

[angelonc]

Thanks for your reply!

I believe they all operate at 1.5V, so hopefully that won't be a problem. The thing I was concerned about was running 3 channels and 2 channels on the same board

 

[willard]

Thanks for your reply!

I believe they all operate at 1.5V, so hopefully that won't be a problem. The thing I was concerned about was running 3 channels and 2 channels on the same board

You can't run dual channel and triple channel at the same time. In fact, you can't run dual channel at all on a triple channel board. It's triple or single, no other options.

Here's the rundown on how this all works. First, your memory is going to throttle back to its slowest module, both in frequency and latency. It's also possible that you'll have stability issues if voltages don't match (1.5v is standard, but 1.65v kits are very common).

Assuming everything works correctly, your computer is going to then be operating in single channel mode, because it doesn't have matched modules in its channels. So, your memory bandwidth is going to go down. A lot. By doing this you'll go up to 14GB of memory from 6GB. Unless you're doing rendering or 3D modeling, there's literally no benefit to this extra capacity (99% of the time, even under heavy multitasking while running games your computer won't use more than 5GB).

So, at this point you've spent money to reduce your memory speed and done nothing to improve system performance. I'd say this is a fairly bad idea.

 

[angelonc]

You can't run dual channel and triple channel at the same time. In fact, you can't run dual channel at all on a triple channel board. It's triple or single, no other options.

Here's the rundown on how this all works. First, your memory is going to throttle back to its slowest module, both in frequency and latency. It's also possible that you'll have stability issues if voltages don't match (1.5v is standard, but 1.65v kits are very common).

Assuming everything works correctly, your computer is going to then be operating in single channel mode, because it doesn't have matched modules in its channels. So, your memory bandwidth is going to go down. A lot. By doing this you'll go up to 14GB of memory from 6GB. Unless you're doing rendering or 3D modeling, there's literally no benefit to this extra capacity (99% of the time, even under heavy multitasking while running games your computer won't use more than 5GB).

So, at this point you've spent money to reduce your memory speed and done nothing to improve system performance. I'd say this is a fairly bad idea.

Thanks for your reply Willard.

I do want a high amount of RAM, because I do a lot of fMRI data analysis which can eat up RAM incredibly fast (some of the machines at work have 32GB RAM for running segmentation algorithms). I'm also getting into video editing, and much of the software used for such has a minimum ram requirement of 6GB.

Could you maybe explain the channel modes a bit more? I have increased the amount of memory, but how will operating in single channel mode effect memory performance?

I have not yet opened the RAM package, so returning it is still an option. Would I be better off returning it for another set of 2x3GB sticks?

 

[willard]

Thanks for your reply Willard.

I do want a high amount of RAM, because I do a lot of fMRI data analysis which can eat up RAM incredibly fast (some of the machines at work have 32GB RAM for running segmentation algorithms). I'm also getting into video editing, and much of the software used for such has a minimum ram requirement of 6GB.

Makes sense to up your memory then. However, you really need to stick to triple channel kits. If you can, return the dual channel kit, because it's going to be detrimental to your machine.

Could you maybe explain the channel modes a bit more? I have increased the amount of memory, but how will operating in single channel mode effect memory performance?

Sure thing. Your motherboard has three "channels" on it. It will typically have more than three slots, however, so each channel has two slots that we'll call A and B.

So, if you put identical modules in slots 1A, 2A and 3A, your computer can address them all at the same time through their own channels. This provides a theoretical 200% speed increase (won't be seen in most cases, though your applications are probably the ones where you do). If you then go and put another set of modules (have to be identical to each other, but not necessarily the ones you already have) in 1B, 2B and 3B, you'll still operate in triple channel mode because those sticks can also be accessed at the same time.

Things change, however, when you do something like fill 1A, 2A and 3A, then populate 1B and 2B but not 3B. The memory controller can no longer guarantee that it can access three modules simultaneously because channel 3 is now very different from channels 1 and 2. Instead, it now has to address them one at a time.

I have not yet opened the RAM package, so returning it is still an option. Would I be better off returning it for another set of 2x3GB sticks?

Yes. You should also check your BIOS to get the frequency, voltage and timings of the memory you've already got, and get a kit that matches as closely as possible. It will simplify things.

 

[angelonc]

Best answer selected by angelonc.

 

[angelonc]

Great, I think I will go ahead and return the RAM that I got and stick with the three channel kits, thanks for all your help!

 

[willard]

Glad to be of assistance!