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Xeon L3426 not working with R ECC memory, but with E ECC?!


I’m upgrading 4 Dell R310 servers from the Xeon L3406’s in them to Xeon L3426’s.

The systems all came with 2 (2x1GB) PC3L-10600E DIMMs. I looked on Intel’s website for RAM support for the Xeon L3426’s and it says ECC supported. So I purchased some RAM along with the CPU’s. However, I didn’t get E, I got R. Not thinking there’s going to be a issue (nothing noted on Intel’s website).

Installed the first CPU, and RAM…system starts, fans full tilt?! What?!
Change RAM from the R to the E…system boots just fine.

So are these Xeon L34X6’s CPU’s not compatible with R ECC DIMMs? only E ECC DIMMs?



Yup, registered dimms are electrically different. Wikipedia says unbuffered only.

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I tried some PC3-8500R - boot, no post.
I tried some PC3-8500U - boot, no post.
I went back to the PC3-8500E - boot, post.

I’m very irritated with Intel right now, as their documentation for this is extremely lacking. It’s sad that a Wiki, made by users, has to be made to document this.



There is very detailed documentation on memory compatibility in the R310 Technical Guide.

The Xeon L3406 does not support registered DIMMs but the Xeon L3426 does.

Are your registered DIMMs quad-rank? Note that you cannot populate all 6 slots with quad-rank DIMMs, only up to 4.



Intels documentation says Xeon L3426 supports up to 32GB of memory over 2 channels, so 8GB per DIMM should work.

I tried 4x 8GB DIMMs of Samsung PC3 8500R memory. With the Xeon L3426 socketed, it wouldn’t boot.

I also had a few sticks of 4GB PC3 8500R. That too would not boot.

I tried 4GB PC3 8500U and that wouldn’t boot.

I went back to the 1GB PC3 10600E memory, and it works fine.

So this is what I gathered thus far; the L34XX will use Unbuffered ECC memory, just not Buffered ECC memory, and will not work with Unbuffered non-ECC memory. Please correct me if I’m wrong.

Looking over the documentation you just sent, I skipped over one small detail, that the R310 will only see up to 16GB total of Unbuffered ECC memory, but will register up to 32GB of Buffered ECC memory. So from this, looks like I need to get different CPU’s.

Looks like I should have did a bit more research on this, and missed a few tid bits of IMPORTANT information.