Core i7 3930K compatibility with RDIMM?

Pri

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Jul 30, 2014
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Before I begin, I want to first state I know that the Core i7 3930K does not support ECC. My intention in using ECC RDIMM's is I have a dual socket workstation motherboard which can be used with only a single socket occupied.

I intend to use the Core i7 3930K in this motherboard for a temporary basis until I get two XEON's. But I need to buy Memory now.

The motherboard itself lists compatibility with both the Core i7 3930K and RDIMM's but they are listed separately in the CPU QVL and then in the RAM QVL. The two have not been to my research tried together.

So I'm curious, will the 3930K work with ECC RDIMM memory or it will it not even boot? And again I'm not looking for ECC to actually function as this is just a stop-gap processor until I get my XEON's.

If nobody knows I'll play it safe and get ECC UDIMM which I know does work 100% but they are a bit more pricey and the voltage is higher so I'd prefer to go with the RDIMM's.

Thanks for any insight guys! :)
 

mattlach

Active Member
Aug 1, 2014
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I don't know for sure, as I have not seen anyone testing this, but I am leaning towards no.

The memory controller is on the CPU's these days, and unless they specifically support the technology it usually doesn't work.

Follow up question:

Why use RDIMMS in a workstation? Unless you absolutely need them the buffer makes you lose a clock cycle, so they actually wind up being slower.

Unless you are doing some very specific things, even ECC is mostly wasted in Desktop/Worstation type situations, but if you absolutely need ECC, go with the ECC Udimms. They DO come in low voltage varieties as well, but I wouldn't worry about that too much. The electricity usage of your RAM is ridiculously small compared to the rest of the components in your system, so I doubt you'd see a real difference.

Personally all my clients use non ECC RAM. I use ECC in my servers. The only time I'd consider using ECC in a desktop/workstation is if it were doing certain very specialized scientific calculations where the rare flipped bit could cause real problems.
 

Pri

Active Member
Jul 30, 2014
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It's for a 4U server. It's just a Workstation/Server motherboard.

I ended up buying 64GB of ECC UDIMM's instead of RDIMM as no one knew if it would work with RDIMM's - But I'm not that bothered about it as I managed to get v1.35 UDIMM's at a lower price from a different vendor. Still Kingston :)
 
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Mike

Member
May 29, 2012
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Before I begin, I want to first state I know that the Core i7 3930K does not support ECC. My intention in using ECC RDIMM's is I have a dual socket workstation motherboard which can be used with only a single socket occupied.

I intend to use the Core i7 3930K in this motherboard for a temporary basis until I get two XEON's. But I need to buy Memory now.

The motherboard itself lists compatibility with both the Core i7 3930K and RDIMM's but they are listed separately in the CPU QVL and then in the RAM QVL. The two have not been to my research tried together.

So I'm curious, will the 3930K work with ECC RDIMM memory or it will it not even boot? And again I'm not looking for ECC to actually function as this is just a stop-gap processor until I get my XEON's.

If nobody knows I'll play it safe and get ECC UDIMM which I know does work 100% but they are a bit more pricey and the voltage is higher so I'd prefer to go with the RDIMM's.

Thanks for any insight guys! :)

With the ever increasing amounts of RAM i would say the chances of memory corruption increases a lot with the technology being more or less equal as before. It makes less sense to still create computer hardware that can not utilize parity as it comes at the cost of only an extra memory chip.
 

Diavuno

Active Member
The I-3/5/7 cannot use ECC registered or unbuffered, only non ecc unbuffered

it's to keep xeons sales up... otherwise budget servers would fly around with I-3's

ecc isnt as fast as plain unbuffered... but for reliability (especially in multi sticks and high volume) it makes sense.

my business and home servers are all ECC, few of the business ones are reg for more room to upgrade.
all workstations are unbuffered except my primary desktop (that i used to game on too!) but with 4x gb or ram across 12 sticks... ecc masde sense...

also I was upgrading my servers XD
 

Pri

Active Member
Jul 30, 2014
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The I-3/5/7 cannot use ECC registered or unbuffered, only non ecc unbuffered

it's to keep xeons sales up... otherwise budget servers would fly around with I-3's

ecc isnt as fast as plain unbuffered... but for reliability (especially in multi sticks and high volume) it makes sense.

my business and home servers are all ECC, few of the business ones are reg for more room to upgrade.
all workstations are unbuffered except my primary desktop (that i used to game on too!) but with 4x gb or ram across 12 sticks... ecc masde sense...

also I was upgrading my servers XD
I don't think you read my original message fully. I already know that the Core i3/i5/i7 do not have the ECC feature. My question wasn't whether the ECC feature can be engaged or used, my question was will these systems turn on with ECC RDIMM's vs ECC UDIMM's - I already know that they will boot up and function perfectly fine with ECC UDIMM's just the ECC feature will be disabled. I did not know if they supported RDIMM's or not.
 
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RTM

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Jan 26, 2014
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The I-3/5/7 cannot use ECC registered or unbuffered, only non ecc unbuffered

it's to keep xeons sales up... otherwise budget servers would fly around with I-3's

ecc isnt as fast as plain unbuffered... but for reliability (especially in multi sticks and high volume) it makes sense.

my business and home servers are all ECC, few of the business ones are reg for more room to upgrade.
all workstations are unbuffered except my primary desktop (that i used to game on too!) but with 4x gb or ram across 12 sticks... ecc masde sense...

also I was upgrading my servers XD
Actually you are wrong, ECC is supported on a lot of low end CPUs, here's an example query, showing a few examples: link
 

Pri

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Jul 30, 2014
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I've already purchased Unbuffered ECC memory. Boots fine with the 3930K with ECC UDIMM btw.
 

Mike

Member
May 29, 2012
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They support it because there are no xeon variants in the lower(st) category, except for maybe the low-power ripoffs
 

Aluminum

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Sep 7, 2012
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Yep there are no standard power dual core xeons, just a few price gouged low TDP models without gpus. (I hate how intel does price segmentation)

Enter the budget celeron/pentium/i3 with ECC support, the OEMs actually move quite a few of them. The lenovo TS140 with i3 is a very popular seller on many sites.

Don't worry though, as soon as a desktop cpu supports something interesting like vpro or all the latest cpu instructions, it loses ecc support, gotta buy that xeon.

Random interesting fact: intel has sold some odd high-clocks low-cores xeons in the past for specialty OEM use, and they charged a ton for them.
If you can get a bios that lets you set multipliers on the C226 chipset, the unlocked pentium G3258 could possibly be the fastest single-threaded server cpu :)
I wonder if some of the HFT guys are playing with them, they use some algorithms that can't multi-thread and want to run with the least latency possible, being a non-HT dual core wouldn't matter then.
 

wildpig1234

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Aug 22, 2016
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rdimm will not work with i7 parts..... i tested this out on two boards, asus p9x79 deluxe and supermicro x9sra....

the x9sra will boot up with i7 and ecc udimm. the p9x79 will not boot up with i7 and ecc udimm, only with non ecc udimm...
 

Pri

Active Member
Jul 30, 2014
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I didn't think this thread would receive any more replies since it's over four years old. But thank you for replying and settling it, it's good to know for sure :)
 

wildpig1234

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Aug 22, 2016
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always good to update old threads :).... the 2011 v2 parts are still very popular now... if anything, even more popular than even 4 yrs ago due to significantly reduced price and much cheaper ddr3 compared to ddr4.

i7-3930k used to be cheaper than e5-1650. i think it's a little of the opposite sometimes now. e5-1650 is much better since you got higher max ram... ability to use ecc and rdimm.
 

Pri

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Jul 30, 2014
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I do agree. I actually changed from a 3930K to a E5-1650 and I switched that out for two E5-2667v2's about 10 months ago. So for me this platform is still very much alive.

I certainly considered buying new, going DDR4 and such but the pricing was nuts. I could pickup two 8 core processors (the E5-2667v2's I mentioned) for 60% of the money that buying 64GB of DDR4 ECC cost. I already had the 64GB DDR3 ECC so it was smarter to upgrade my processors using used parts on ebay than it was to buy the latest and greatest stuff brand new by a long shot.

Funnily enough I now have more CPU power than I need so I'll probably be keeping this setup for a long time yet.
 

wildpig1234

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Aug 22, 2016
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yeah, i like my dual 2667 v2 also... very fast single core speed, more than enough for just about anything...... even though single core it's no comparison to i9-9900k. but for multicore, dual 2667 v2 beats anything around for the same price...

i am still trying to find the perfect single socket 2011 board.... couldn't find one yet that have proper s3 sleep, 16gb rdimm support, oem cpue support (2696 v2), and more than two pcie x16 and at least one x4...... the closest one so far is the lenovo s30, but it doesn't support oem cpu like 2696 v2..... the supermicro x9sra is also good and even better than s30 since it support lrdimm, but i still can't get s3 sleep to work on it properly in win10.... p9x79 only support up to 8gb rdimm...