dual vrs tri-Channel kit on x58

A

Antiflash

Limp Gawd
Joined
Jan 12, 2009
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Without the need of high performance memory, OCZ have some ok prices on DDR3 memory.

If for some reason dual kit (OCZ3P1333LV4GK) is cheaper per memory module than tri-channel kit (OCZ3P1333LV6GK). If I want to populate six slots (12GB) I would prefer to buy 3 dual kits instead of 2 trio-kits but I would like to confirm.
1. Can some one around here confirm that both kits (for the models above) contain the same memory modules?
2. If for budget constrains, can I buy only 2 dual kits and total 8GB and run one channel of an x58 motherboard with only 2GB? Any performance, compatibilty issues?
Thank you.
 
Antiflash said:
Without the need of high performance memory, OCZ have some ok prices on DDR3 memory.

If for some reason dual kit (OCZ3P1333LV4GK) is cheaper per memory module than tri-channel kit (OCZ3P1333LV6GK). If I want to populate six slots (12GB) I would prefer to buy 3 dual kits instead of 2 trio-kits but I would like to confirm.
1. Can some one around here confirm that both kits (for the models above) contain the same memory modules?
2. If for budget constrains, can I buy only 2 dual kits and total 8GB and run one channel of an x58 motherboard with only 2GB? Any performance, compatibilty issues?
Thank you.
Click to expand...

For 1), you cannot be sure. This is because multiple versions of the same memory kit are being made simultaneously at various different factories. Each may be using different ICs. Plus, OCZ (at least on their lower-end performance modules) has been selling multiple different modules with multiple different ICs under the exact same revision number.

For 2), performance will be reduced because running four modules in such a flex mode will increase the total latency in the memory controller. In fact, performance in such a configuration may be lower than a much cheaper system using the same generation of CPU but otherwise identically equipped. (In other words, if you're going to run 8GB via four modules in the long term, you might as well save the money and go for a 'lesser' LGA1156 motherboard and processor instead of LGA1366.)
 
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+1 on what E4g1e said.

Concerning 1) you could post on the OCZ forums about compatibility. Frame the question so that they don't give you a biased response. E.g. I have purchased 2 identical 4GB kit for my P55 board. Now I have upgraded to a X58 board and would like to purchase a 3rd same part number 4GB kit so I can do triple channel. What performance or compatibility problems would I be facing.

Personally (and this is just my opinion) I think your looking at maybe some slower timings in the worst case scenario (see what impact that has in the Anandtech article). DDR3 technology (so long as your not buying the 2000 speed grade) is fairly mature. If your using DDR3-1333 they should work in any decent board otherwise they would not conform to the DDR3 spec and you can ask OCZ for an exchange. All the major brand names test for higher tolerances, so unless you buy no-name brands where they sell you a lower speed as a higher one, you should be able to hit the spec and go a bit higher in OC'ing. I've bought several OCZ DDR2 4GB kits and ended up plugging them into a single board as I upgraded and bought more memory. Using stock setting I've not seen any issues and I'm in fact OC'ing them a bit, but because of what I know about the impact of memory on the overall system, I try to keep this simple and focus on CPU OC'ing, where I can get more bang for the buck. I'm expecting the same for my DDR3 memory, but vendors won't explicitly guarantee it because only triple dimm kits are tested together. It would be significantly more expensive for them to test dual kits with an extra dimm or with other brands. Besides they want to charge you premium for their higher margin products.

Some additional thoughts on 2, you might want to try it out and see what the impact is. Since my board supports dual channel with 2 DIMMs I can't imagine it wouldn't do the same with 4DIMMs. You'll need to read your manual to see which slots exactly to use. Definitely avoid a 3DIMMs + 1DIMM. You might end-up with single channel for everything or an imbalanced triple channel + single channel. My fall back would be to use 6GB (3 dimms) if there is a significant performance going from dual channel to tripple. My guess is that if you have a program that can use that much memory (most are still designed for <3GB) then having more memory (to avoid swap) will bring more performance than dual vs. triple channel.

Read this article and make up your own mind ;) http://www.anandtech.com/memory/showdoc.aspx?i=3589
 
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sfsilicon said:
Definitely avoid a 3DIMMs + 1DIMM. You might end-up with single channel for everything or an imbalanced triple channel + single channel.
Click to expand...

In fact, the manual for the Asus P6T series motherboards clearly explains this imbalanced triple channel + single channel mode. Say, you have four 2GB modules installed in slots A1, A2, B1 and C1. The channel that has the least amount of RAM will be the basis for triple-channel operation (in this case, 2GB would then be multiplied by three). Hence, 6GB would operate in triple-channel and 2GB would operate in single-channel. Same thing happens if you were using five 2GB modules for a total of 10GB. In this case, the remaining 4GB could not run in dual-channel - but would run in single-channel instead. Or, if you were filling up three slots with unequal-sized DIMMs, then the smallest-capacity DIMM would be the base for triple-channel and any remaining memory would then operate in single-channel (for example, if you had 10GB on three DIMMs where one of them was 2GB while the other two were 4GB each, then only 6GB would operate in triple-channel while the remaining 4GB would operate in single-channel).

On that series of boards, the only way to get 8GB (via four 2GB DIMMs) to run entirely in dual-channel would be to fill up A1, A2, B1 and B2 (leaving channel C empty).

Whatever X58 motherboard the OP ultimately gets may vary from the Asus example above.
 
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I'm new here, what a great community!. Thanks for your detailed responses. I'm going over all the info and links provided. I went ahead an bought 2 dual kits for $150 after cashback and rebate. Will only use 6GB out of 8GB and hopefully avoid compatibility issues by having an extra stick as spare. If I have luck and different memory configurations works using all sticks, will probably risk to buy the third memory kit.
Will let you know when parts arrive if they work.
 
I purchased 3 of the G.SKILL DDR3 1600 4GB kits for my i7-920 rig. Everything is running smooth as silk. Now days if you purchase all the ram at the same time I highly doubt you would ever run into an issue.
 
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