OK to add 1x4GB to 2x1GB?

[arnoldh]

I have an ASUS P7H55-M desktop with twin 1GB DDR3 modules 3X1G1333C9 ver 2.3, running on Windows 7 32 bit. I'd like to move to W7 64 bit and increase my memory from 2GB to 6GB. I propose to add one 4GB X4GX3M1A1333C9 module to the existing 2x1GB dual channel modules.

 

Am I correct that I can do this so that the 2x1GB modules continue to operate in dual channel mode?

 

Also, I realise that the 4GB module will be operating in single channel mode. Is it likely that I will in practice lose that much overall PC performance compared with adding 2x2GB modules in dual channel mode (I'm not sure I can find these 2x2GB for sale anyway)?

 

I'm not gaming, and not doing a lot of cpu intensive work, but I am running out of memory sometimes even on 32 bit Windows. So my main aim is to increase my available memory, but I wouldn't want to do that if I'm going to slow down memory access very significantly by adding a single channel module.

[peanutz94]

You can try what you like but there is just no way to guarantee that any two random its would work together as intended. It's possible you may have to lower them to 1066mhz to get them to play nice with each other if at all.

Corsair does not suggest or support mixing/combining memory for this very reason. It can be hit or miss at best.

 

You would be better off to just purchase a matched kit of the capacity you are wanting .

[arnoldh]

You can try what you like but there is just no way to guarantee that any two random its would work together as intended. It's possible you may have to lower them to 1066mhz to get them to play nice with each other if at all.

Corsair does not suggest or support mixing/combining memory for this very reason. It can be hit or miss at best.

 

You would be better off to just purchase a matched kit of the capacity you are wanting .

 

Thanks for the response.

 

I'm confused though. If I understand you right, I may have problems because my existing 1GB 3X1G1333C9 modules are not matched to the new 4GB X4GX3M1A1333C9 module. But I thought these were exactly the same Corsair modules, same speed, latency etc.

 

To take a different example, suppose I wanted 16GB and purchased two sets of 2x4GB matched pairs, then put these into the board as two pairs of dual channel memory. Would this configuration not necessarily work because the two pairs are not matched to each other, only matched within each pair?

 

I'm not doubting what you say, just trying to clarify for myself the recommended configurations when installing modules with the same spec.

[peanutz94]

I'm confused though. If I understand you right, I may have problems because my existing 1GB 3X1G1333C9 modules are not matched to the new 4GB X4GX3M1A1333C9 module. But I thought these were exactly the same Corsair modules, same speed, latency etc.

Yes, you are correct. Even though they are the same exact part number , they are still two totally random kits that have not been matched with your other modules. It may or may not work, but no guarantees.

 

To take a different example, suppose I wanted 16GB and purchased two sets of 2x4GB matched pairs, then put these into the board as two pairs of dual channel memory. Would this configuration not necessarily work because the two pairs are not matched to each other, only matched within each pair?

You would need a matched 4x4gig kit to be guaranteed compatibility and rated speeds. When you use two kits there is a good possibility that you would have to run them at the next lowest SPD or they may not work at all. Your basically facing the same issue. Two totally random kits that were not matched with each other. Corsair tests and packages modules in 2 or 4 stick sets for this very reason.

[arnoldh]

Thanks. I understand now.

 

I will purchase a pair of 2GB modules. If they don't work with the existing 1GB pair, I've at least doubled the memory. I can also try dropping the speed and if the four modules then work together I can compare the system performance of 6GB running at a slower speed with 4GB running faster.

 

Thank you for your help.

[arnoldh]

Well, I got lucky. The additional 2x2GB pair along with the existing 2x1GB pair works fine.

 

The two 1GB modules were in slots A1 and B1, and I added the 2GB modules in slots A2 and B2. Does it matter whether the 2GB modules are in higher or lower numbered slots than the 1 GB modules?

[peanutz94]

It makes no difference at all. Glad to hear it worked out for you.

[arnoldh]

Thanks for your help