Dual Rank Memory - Is there a performance advantage?
Hi - I know there are already a few threads relating to the single vs dual rank memory arguement but can anyone tell me if there is any performance benefit in using dual rank memory in a server.
I am speccing a large server to run SQL Server 2005 and need to know whether to go for the dual rank memory.
The single is cheaper but cost is not relevant. I need to be able to deliver best performance.
Thx...
I am speccing a large server to run SQL Server 2005 and need to know whether to go for the dual rank memory.
The single is cheaper but cost is not relevant. I need to be able to deliver best performance.
Thx...
The maximum performance of your memory subsystem is achieved if you utilize all four ranks in each memory channel. Whether you do this with four single-rank DIMMs, or two dual-rank DIMMs doesn't matter. So the answer to your question depends on the memory configuration you're using.
If your system supports dual channel memory, then you want to have 4 ranks in each channel ... in this case that's often achieved by using four dual-rank DIMMs (two for each channel).
Do NOT, however, mix single and dual rank DIMMS ... that will tend to reduce performance, as the chipset will not be able to uniformly distribute addresses.
If your system supports dual channel memory, then you want to have 4 ranks in each channel ... in this case that's often achieved by using four dual-rank DIMMs (two for each channel).
Do NOT, however, mix single and dual rank DIMMS ... that will tend to reduce performance, as the chipset will not be able to uniformly distribute addresses.
I don't see why you shouldn't mix ranks; say you have 6 slots of interleaved RAM available on the motherboard, one dual rank 4GB pair plus two single ranked 2GB pairs does uniformly distribute the memory surely?
i think garycase ment dont mix duel and single rank in paired slots.
most MB that have say 4 memory slots will have 1 and 3 and 2 and 4 as seperate channels.
so if you put memory in slots 1 and 2 they will run as single channel mode. however if you put the same modules in slots 1 and 3 they will run duel channel.
however you should not mix single and duel channel modules in the same MB channel :)
so you could have single rank pairs in slots 1 and 3 and duel rank modules in slots 2 and 4 and be ok.
but not single modules in slots 1 and 2 and dule modules in slots 3 and 4. as this would result in mismatched pairs and reduce proformance.
most MB that have say 4 memory slots will have 1 and 3 and 2 and 4 as seperate channels.
so if you put memory in slots 1 and 2 they will run as single channel mode. however if you put the same modules in slots 1 and 3 they will run duel channel.
however you should not mix single and duel channel modules in the same MB channel :)
so you could have single rank pairs in slots 1 and 3 and duel rank modules in slots 2 and 4 and be ok.
but not single modules in slots 1 and 2 and dule modules in slots 3 and 4. as this would result in mismatched pairs and reduce proformance.
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Check the Server specs. In general I have not seen this. so I would not bother.
I hope this helps !