Cantiga to Support 4GB or 8GB?

[mcarling]

What is the maximum DDR3 memory capacity that will be supported by the Intel Cantiga mobile chipset expected in Q2 2008? I'm expecting it will be 4GB, but would be happily surprised if it were to be 8GB.

[Adrian Wong]

No idea, but 8GB should be possible. However, with most notebooks supporting only 2 SO-DIMM slots, it will be almost impossible to reach exceed 4GB unless manufacturers start churning out DDR3 SO-DIMMs with capacities greater than 2GB.

[mcarling]

I agree that laptops are unlikely to have more than two SO-DIMM slots. However, I think that if Cantiga were to support 8GB, then manufacturers like Corsair would offer 4GB DDR3 SO-DIMMs (at high prices). I know that Santa Rosa supports up to 4GB maximum.

[Adrian Wong]

Originally Posted by mcarling

I agree that laptops are unlikely to have more than two SO-DIMM slots. However, I think that if Cantiga were to support 8GB, then manufacturers like Corsair would offer 4GB DDR3 SO-DIMMs (at high prices). I know that Santa Rosa supports up to 4GB maximum.

Hmm.. The thing is I don't think they are capable of delivering high-capacity DDR3 SO-DIMM modules. Even regular DDR3 DIMMs are rare.

BTW, I'm not even sure if there are 4GB DDR2 SO-DIMMs. The biggest I've come across is a 3GB DDR2 SO-DIMM.

[mcarling]

Originally Posted by Adrian Wong

Hmm.. The thing is I don't think they are capable of delivering high-capacity DDR3 SO-DIMM modules. Even regular DDR3 DIMMs are rare.

BTW, I'm not even sure if there are 4GB DDR2 SO-DIMMs. The biggest I've come across is a 3GB DDR2 SO-DIMM.

I would not expect there to be any 4GB SO-DIMMs shipping yet because there is no realistic application for them before a mobile chipset supporting 8GB ships. Virtually all high-end laptops have 2 SO-DIMM slots so, with chipsets currently supporting at most 4GB, what would be the point of a 4GB SO-DIMM?

Someday, there will be a mobile chipset supporting 8GB and I expect 4GB SO-DIMMs will start shipping at the same time or shortly after. I just don't know whether that chipset will be Cantiga or a successor. That's what I'd like to know.

Edited to add: I just checked and full size DIMMs are shipping in 8GB and 16GB capacities, so a 4GB SO-DIMM should be technically possible.

[Chai]

Originally Posted by mcarling

I would not expect there to be any 4GB SO-DIMMs shipping yet because there is no realistic application for them before a mobile chipset supporting 8GB ships. Virtually all high-end laptops have 2 SO-DIMM slots so, with chipsets currently supporting at most 4GB, what would be the point of a 4GB SO-DIMM?

Someday, there will be a mobile chipset supporting 8GB and I expect 4GB SO-DIMMs will start shipping at the same time or shortly after. I just don't know whether that chipset will be Cantiga or a successor. That's what I'd like to know.

Edited to add: I just checked and full size DIMMs are shipping in 8GB and 16GB capacities, so a 4GB SO-DIMM should be technically possible.

That is the whole point! Chicken and egg situation!

[Adrian Wong]

Originally Posted by mcarling

I would not expect there to be any 4GB SO-DIMMs shipping yet because there is no realistic application for them before a mobile chipset supporting 8GB ships. Virtually all high-end laptops have 2 SO-DIMM slots so, with chipsets currently supporting at most 4GB, what would be the point of a 4GB SO-DIMM?

Someday, there will be a mobile chipset supporting 8GB and I expect 4GB SO-DIMMs will start shipping at the same time or shortly after. I just don't know whether that chipset will be Cantiga or a successor. That's what I'd like to know.

Edited to add: I just checked and full size DIMMs are shipping in 8GB and 16GB capacities, so a 4GB SO-DIMM should be technically possible.

Well, of course the chipset will have to support 8GB before memory manufacturers start shipping 4GB SO-DIMMs. However, I suspect that even if Cantiga supports 8GB, you will not find 4GB modules for the next year or so.

The 8GB and 16GB DIMM modules you see are all registered DIMMs that use stacked dies. It's unlikely for memory manufacturers to deliver unbuffered SO-DIMMs in 4GB capacities unless they start delivering higher capacity DDR3 chips.

When Cantiga is launched with DDR3 support, memory manufacturers will have trouble producing DDR3 SO-DIMMs in lower capacities (512MB, 1GB), much less worry about catering to the super-high-end market asking for 2GB and 4GB SO-DIMMs.

Also, there is the issue of cost. A 2GB DDR2 SO-DIMM is already extremely expensive, and bought only by a very small, niche market. A 2GB DDR3 SO-DIMM will be even more expensive. A 4GB DDR3 module will, of course, be prohibitively expensive. Therefore, it's likely that the potential market is so small, companies like Kingston / Crucial will not feel it's worth investing their money into building these high-capacity SO-DIMMs.

[mcarling]

Originally Posted by Adrian Wong

Well, of course the chipset will have to support 8GB before memory manufacturers start shipping 4GB SO-DIMMs. However, I suspect that even if Cantiga supports 8GB, you will not find 4GB modules for the next year or so.

The 8GB and 16GB DIMM modules you see are all registered DIMMs that use stacked dies. It's unlikely for memory manufacturers to deliver unbuffered SO-DIMMs in 4GB capacities unless they start delivering higher capacity DDR3 chips.

When Cantiga is launched with DDR3 support, memory manufacturers will have trouble producing DDR3 SO-DIMMs in lower capacities (512MB, 1GB), much less worry about catering to the super-high-end market asking for 2GB and 4GB SO-DIMMs.

Also, there is the issue of cost. A 2GB DDR2 SO-DIMM is already extremely expensive, and bought only by a very small, niche market. A 2GB DDR3 SO-DIMM will be even more expensive. A 4GB DDR3 module will, of course, be prohibitively expensive. Therefore, it's likely that the potential market is so small, companies like Kingston / Crucial will not feel it's worth investing their money into building these high-capacity SO-DIMMs.

Thanks. You've just presented a good case for why Intel probably won't support 8GB with Cantiga. For the same reasons, I have been expecting 8GB support from a mobile chipset only subsequent to Cantiga. I was hoping someone here might know for sure.

Does anyone here remember whether the first mobile chipsets to support DDR2 supported the same or an increased total RAM capacity? The argument above would tend to suggest that it should have been the same.

[Adrian Wong]

Originally Posted by mcarling

Thanks. You've just presented a good case for why Intel probably won't support 8GB with Cantiga. For the same reasons, I have been expecting 8GB support from a mobile chipset only subsequent to Cantiga. I was hoping someone here might know for sure.

Does anyone here remember whether the first mobile chipsets to support DDR2 supported the same or an increased total RAM capacity? The argument above would tend to suggest that it should have been the same.

I'll check with Intel but no guarantees. They are quite tight-lipped about "future products".

Well, I don't think that logic applies. It would most likely be designed around what Intel expects the capacity of RAM chips to be in the near future.

If DRAM manufacturers cannot deliver the capacity necessary for a 2GB SO-DIMM, then it would be quite pointless for Intel to add support for 8GB of memory.

Right now, looking at desktop RAM, it appears like DDR2 DRAM is limited to 2Gb (256MB) per chip. This means DIMMs will have a maximum capacity of 4GB per module. SO-DIMMs will have a capacity of 2GB per module. So, even if Intel supports 8GB, the industry doesn't have the capability to deliver the DRAM density required.

BTW, if you check DDR3 DRAM density now, it looks like DDR3 is limited to 1Gb (128MB) per chip. So maximum capacity for a DDR3 DIMM is stuck at 2GB and SO-DIMMs will be stuck at 1GB for now. Doubling that will take time, probably 1-2 years. We would probably not see them quadrupling the density for another 2-3 years IMHO.

In that sense, I don't think Intel will add support for 8GB of RAM in Cantiga. But again, I will double-check with them.