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March 4th, 2012 06:00
How to combine different DIMMs for R410?
I have 2 R410 boxes with the following RAM configuration:
1) 1 pc of 8GB RAM (originally in the box, but NOT)
4Rx8 (Qaud Rank x 8bit density)
1 pc of 8GB RAM (from eBay)
2Rx4 (Dual Rank x 4bit density)
2) 2 pc x 4GB RAM (originally in the box)
2R x 4 (Dual Rank x 4bit density)
In addition I bought these DIMMs:
2 pc x 4GB RAM (from ebay)
2R x 8 (Dual Rank x 8bit density)
My goal: two servers with 16GB in each one with optimal permance
My issue::
- on the 1st box I receive "Unsupported memory configuration. DIMM mismatch" error during BIOS initialization. I have no idea if this just a warning or real problem.
My questions:
- how I should combine my DIMMs into these 2 servers?
- is there specific BIOS RAM mode I should use [there are Optimizer/Mirror/Advanced ECC]?
TIA,
Vitaly
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theflash1932
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16.3K Posts
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March 4th, 2012 09:00
Maybe page 119 of the manual will be of some help:
http://support.dell.com/support/edocs/systems/peR410/en/HOM/PDF/HOM.pdf
The only optimized configurations you can do with the DIMM's you listed is this:
Server 1: 2x4GB, x8
Server 2: 2x4GB, x4
The fact that you are getting "unsupported memory configuration" with the two 8GB DIMM's indicates that while both 4R and 2R DIMM's are supported, they cannot be mixed (may mean the layout - x4,x8 - cannot be mixed either - you could confirm with your 4GB DIMM's):
You can use a single 8GB DIMM per machine, but that configuration is not optimal either.
Running your system in an unsupported configuration could lead to an unstable system.
My advice? Get another 8GB DIMM that matches one of the two you have.
vitaly_il
3 Posts
1
March 5th, 2012 00:00
Thank you! Buying new DIMMs is probably the safest way.
In fact, prior to send my question I read Dell's manuals and I'm little confused. It seems that mixing DIMMs with different ranking is supported in some cases, but it is pretty hard to understand all different combination.
vitaly_il
3 Posts
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March 5th, 2012 02:00
is this configuration supported:
Server # 1
16GB in Total, Different ranking but same density:
1 pc of 8GB RAM - 4R x 8 (Qaud Rank x 8bit density)
2 pc x 4GB RAM - 2R x 8 (Dual Rank x 8bit density)
Server #2
16 GB Configuration, same ranking and same density:
1 pc of 8GB RAM - 2R x 4 (Dual Rank x 4bit density)
2 pc x 4GB RAM - 2R x 4 (Dual Rank x 4bit density)
theflash1932
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16.3K Posts
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March 5th, 2012 08:00
Is it supported? Probably not "supported", but it also doesn't appear to be prohibited either.
Is it optimal? No. An optimal configuration would have identical DIMM's.
You can try it. From the docs, I might assume that the only limitation with mixing dual and quad ranks is that you just can't put any quad ranks in slot 4 (closest to the processor); since you only have three DIMM's any way, it might work to put the 8GB DIMM in slot 1 (second slot from the processor) and the 4GB DIMM's in 2 and 3.
Also, the x8 DIMM's do not support SDDC, also called Chipkill, which greatly reduces the amount of correctable errors and the effect of uncorrectable errors in memory ... so, if one is to be more critical than the other, you might consider using the one with x4 for that purpose.