About 13 years ago, I was assembling some Xeon servers we had purchased from IBM (think xSeries 365 or so) and bought some dual-rank RAM to fill them out. I don't recall the exact number but only a portion of the memory worked and IBM explained that their BIOS addressed the memory by addressable chip, and we had simply put more chips in the slots than they had available. It wasn't documented, and they worked with our memory rep to replace the (of course) non-refundable RAM. Probably not an issue for our desktops, but I would be concerned with higher memory counts like you'd find with people trying to build virtualization hosts.
I have the same kit with 16GB modules: 64GB DDR4 3200@14-14-14 with a Row Refresh Cycle Time @ 560 with a command rate of 2T.
5 Questions:
1) What is the Row Refresh Cycle Time for this kit. (I may be a complete idiot here, but I suspect the tRFC is where RAM producers mask their latency in order to get better numbers in the big three Madison Avenue metrics [CL, tRCD, & tRP]) 2) What is the voltage. 3) What is the latency and bandwidth compared to 4x16GB of the same amount of memory rated at these speeds. 4) What is the latency and bandwidth @ 4x32GB for both samples. 5) What is the command rate of the 32GB modules.
I don't think 4x32 is possible with these. If you look up the supported MBs they are all limited to 2 slots with only 1 DPC.
With the article saying "essentially two UDIMM modules on one PCB, with double chips, double ePROM" I take that to mean that these boards will see it as 1 DPC when one of these is installed. None of the consumer chips support more than 2 DPC so should not allow you to do 4X32 because it would see it as 4 DPC.
Honestly like how tall these are. It kind of aesthetically balances out the rest of the system since cards in the PCIe slots tend to be might taller, not even usually half-height either. Of course as mentioned it might not fit with certain coolers. But I do like this soluation. It probably ends up cheaper per DIMM to double up the ICs rather than getting the newer higher capacity IC. I know most will say they don't need the RAM but for my multi-use system, I found lots of ways to make use of my 64GB of RAM.
This reminds me of double stacking DIPs in order to get twice as much RAM when pre 30-pin SIMM motherboards couldn't support enough for newer programs. Combine that with an ISA RAM card and you could get an ungodly amount of system memory - up to the 16MB limit on 80286 CPUs.
AIUI at best they'd appear as 50% capacity in any other board because cramming 2 dimms into a single socket required repurposing some of the IO pins from standard.
Can I install one 16GB Tridentz RAM stick with the same timings (14-14-14-34) combined with one 32GB of the double capacity with the same timings? I only have space for one stick increased in height with my cooler in the DAN case. I wonder if I can even buy one stick at once. Hmm.
We’ve updated our terms. By continuing to use the site and/or by logging into your account, you agree to the Site’s updated Terms of Use and Privacy Policy.
Facebook
Twitter
RSS
17 Comments
Back to Article
Another IT Guy - Friday, November 9, 2018 - link
About 13 years ago, I was assembling some Xeon servers we had purchased from IBM (think xSeries 365 or so) and bought some dual-rank RAM to fill them out. I don't recall the exact number but only a portion of the memory worked and IBM explained that their BIOS addressed the memory by addressable chip, and we had simply put more chips in the slots than they had available. It wasn't documented, and they worked with our memory rep to replace the (of course) non-refundable RAM. Probably not an issue for our desktops, but I would be concerned with higher memory counts like you'd find with people trying to build virtualization hosts.alacard - Friday, November 9, 2018 - link
I have the same kit with 16GB modules: 64GB DDR4 3200@14-14-14 with a Row Refresh Cycle Time @ 560 with a command rate of 2T.5 Questions:
1) What is the Row Refresh Cycle Time for this kit. (I may be a complete idiot here, but I suspect the tRFC is where RAM producers mask their latency in order to get better numbers in the big three Madison Avenue metrics [CL, tRCD, & tRP])
2) What is the voltage.
3) What is the latency and bandwidth compared to 4x16GB of the same amount of memory rated at these speeds.
4) What is the latency and bandwidth @ 4x32GB for both samples.
5) What is the command rate of the 32GB modules.
kpb321 - Friday, November 9, 2018 - link
I don't think 4x32 is possible with these. If you look up the supported MBs they are all limited to 2 slots with only 1 DPC.With the article saying "essentially two UDIMM modules on one PCB, with double chips, double ePROM" I take that to mean that these boards will see it as 1 DPC when one of these is installed. None of the consumer chips support more than 2 DPC so should not allow you to do 4X32 because it would see it as 4 DPC.
kpb321 - Friday, November 9, 2018 - link
**will see it as 2 DPC when one of these is installedyuhong - Friday, November 9, 2018 - link
The 16Gbit DDR4 based DIMMs should also be easier to find this month.dwzl - Friday, November 9, 2018 - link
How does one buy these?CheapSushi - Friday, November 9, 2018 - link
Honestly like how tall these are. It kind of aesthetically balances out the rest of the system since cards in the PCIe slots tend to be might taller, not even usually half-height either. Of course as mentioned it might not fit with certain coolers. But I do like this soluation. It probably ends up cheaper per DIMM to double up the ICs rather than getting the newer higher capacity IC. I know most will say they don't need the RAM but for my multi-use system, I found lots of ways to make use of my 64GB of RAM.PeachNCream - Saturday, November 10, 2018 - link
This reminds me of double stacking DIPs in order to get twice as much RAM when pre 30-pin SIMM motherboards couldn't support enough for newer programs. Combine that with an ISA RAM card and you could get an ungodly amount of system memory - up to the 16MB limit on 80286 CPUs.DigitalFreak - Saturday, November 10, 2018 - link
Seems like a pretty limited market. Any motherboard larger than mini-ITX should have 4 DIMM slots anyway.CheapSushi - Sunday, November 11, 2018 - link
I'd want them even on ATX or EATX. I just like the tall RAM.Lolimaster - Sunday, November 11, 2018 - link
And if you're going the max of 64GB for just a non-HEDT system you're kind of failing, even if it's a 2700X..Lolimaster - Sunday, November 11, 2018 - link
That time (2 years ago) when you could get 2x8GB for less than $80 and 2x16GB kits for 160-200...Valantar - Monday, November 12, 2018 - link
I hope AT will test these across a few motherboards to see if they really only work in the ones mentioned :)DanNeely - Monday, November 12, 2018 - link
AIUI at best they'd appear as 50% capacity in any other board because cramming 2 dimms into a single socket required repurposing some of the IO pins from standard.husky - Wednesday, November 14, 2018 - link
Can I install one 16GB Tridentz RAM stick with the same timings (14-14-14-34) combined with one 32GB of the double capacity with the same timings? I only have space for one stick increased in height with my cooler in the DAN case. I wonder if I can even buy one stick at once. Hmm.