for everyone building a "New System" using the i7 CPU and x58 mainboards..

[Heater]

All

be very careful on what DDR3 memory you chose for your system, I work with the Intel guys on a weekly basis and they are seeing a lot of problem with the memory vs. CPU this is due to the memory voltage... the spec states 1.65 MAX... i.e. you need to be using the low voltage DIMM's or you are asking for problems... they suggest to check the recommendations for the main board and if there are none then follow the spec for the CPU / X58 chip set.

[eagl]

That seems to make sense when added to the recent article on Anandtech about the integrated memory controller being a bit twitchy when it comes to overclockability.  Apparently some i7 batches have significantly better IMCs than others, and it can dramatically limit overclockability.

Not that everyone is trying to overclock, but if the overclockers are having problems with the memory controller then it makes sense that everyone else might see generic memory compatibility problems arise on occasion especially if they have a cpu with one of the weaker memory controllers or a mobo that doesn't handle the higher voltages very well.

[Reschke]

Thanks for the heads up. I hope that things are tweaked and worked out well enough by the time that I get to building my system in a few months.

[TilDeath]

If your using the i7 setup and to take advantage of the design of the i7 processors, you should be using Triple Channel memory which is "low voltage".  The voltages vary from manufacturer to manufacture, but at between 1.5 and 1.7 volts (check with your makers website for settings).  If you don't put more then 1.65 volts to the CPU your fine.  As with all component builds, you should be going into your BIOS and setting the memory voltage and timings manually.

[Bino]

I'm curious about RAM on these triple-channel motherboards...

Is there any benefit to fully populating the six DIMM slots (i.e, six one-gigabyte DIMMs)?  Does this allow the memory controller to better interleave RAM access?

[I understand that if I use only half of the slots (i.e., three two-gigabyte DIMMs) I preserve the ability to add more, later.]

TIA   


PS: Sitting by the mailbox, waiting for that tax refund check...   

[TilDeath]

I'm curious about RAM on these triple-channel motherboards...

Is there any benefit to fully populating the six DIMM slots (i.e, six one-gigabyte DIMMs)?  Does this allow the memory controller to better interleave RAM access?

[I understand that if I use only half of the slots (i.e., three two-gigabyte DIMMs) I preserve the ability to add more, later.]

TIA   


PS: Sitting by the mailbox, waiting for that tax refund check...   

As with all memory the lessor the number of sticks generally the more stable a system.

To answer your question, Three 2Gb sticks are better then Six 1Gb. The On-die memory controller is directly connected to the processor.   With Three channel memory, each channel can support one or two DDR3 DIMMs.  The DIMMs should be installed in sets of three, not two.

The front side bus is replaced by the QuickPath interface (QPI) and this is where the Overclocking is done along with system tweeking.  One of the reasons people get worried about Memory voltages and i7 processors is the processors recommended max voltage at 1.65 (I have not gone over 1.42volts to the processor ** 920 at 4.2GHz**), therefore you would have to make sure to get triple channel memory to keep the board in specs.  With all memory you should set its timings and voltages in the BIOS manually.

[Bino]

As with all memory the lessor the number of sticks generally the more stable a system.

Interesting!  Is this just due to the normal variations of mass production?

To answer your question, Three 2Gb sticks are better then Six 1Gb. The On-die memory controller is directly connected to the processor.   With Three channel memory, each channel can support one or two DDR3 DIMMs.  The DIMMs should be installed in sets of three, not two.

I get it about adding the triple-channel DIMMs in sets of three, and I understand how multi-channel RAM access works better than the old single-channel design, but I missed why 3 x 2Gb is better than 6 x 1Gb.  Sorry.

The front side bus is replaced by the QuickPath interface (QPI) and this is where the Overclocking is done along with system tweeking.  One of the reasons people get worried about Memory voltages and i7 processors is the processors recommended max voltage at 1.65 (I have not gone over 1.42volts to the processor ** 920 at 4.2GHz**), therefore you would have to make sure to get triple channel memory to keep the board in specs.  With all memory you should set its timings and voltages in the BIOS manually.

Thanks! 

[TilDeath]

Interesting!  Is this just due to the normal variations of mass production?

I get it about adding the triple-channel DIMMs in sets of three, and I understand how multi-channel RAM access works better than the old single-channel design, but I missed why 3 x 2Gb is better than 6 x 1Gb.  Sorry.

Thanks! 

If you look at memory sets, some manufactures state "matched pairs" or "tested pairs". The reason they do this is so that the memory run at the very close specs together.  There is an amount of tolerance that is allowed between mated pairs for them to be pairs, more then the allowed amount and they will not sync together well and not be matched pairs.

At posted stock speed they should run fine together, but setting the QPI (i7s) higher the sticks may not agree and sync up causing BSD because of memory failure.  This could also happen at stock speeds without any overclocking when using unmatched pairs, is it common for this to happen, no but it does happen.  You also have a higher chance of getting a bad stick.  Your adding variables buy doubling the number of sticks.  The more DIMMs you use the better the chance if one fails not being able to locate the bad stick without running Memtest on each stick for 2 hours.  You could place the sticks in one by one and still have the system boot, but in combination there is a failure.

Smaller DIMMs have faster timings but with DDR3 Dual or Triple Channel they timings are not all that great anyhow but the speed compensates for the higher timings.  Hope this helps