New HUDIMM memory specification debuts with goal of slashing DDR5 prices during RAM shortages — A new, cheaper memory standard with half the bandwidth and half the capacity

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DDR5 sticks have 2x 32-bit subchannels, otherwise.

ASRock HUDIMM standard
(Image credit: ASRock)

Thanks to the AI boom, component prices have skyrocketed in the past few months, leading constituents to come up with creative ways to fight the RAMpocalypse. ASRock has previously introduced a motherboard with both DDR4 and DDR5 slots to help alleviate the crisis, but now it's teaming up with Intel and TeamGroup to launch "HUDIMM" — a new type of DDR5 RAM that can potentially help you save money.

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ASRock HUDIMM standard

(Image credit: ASRock)

According to ASRock, "two sub-channel (2*32-bit)" architecture is beneficial for high-capacity single DIMM module, however, it is not so practical for current PC market." That being said, HUDIMM has asymmetrical dual-channel support at the BIOS level. This should allow you to mix and match different DDR5 RAM to circumvent the single subchannel limitation and achieve higher bandwidth, while still maintaining compatibility.

For instance, an 8 GB HUDIMM stick paired with a 16 GB UDIMM stick will run in proper dual-channel mode with at least 3x 32-bit subchannels active — one from the HUDIMM and two from the standard UDIMM. This Frankenstein 24 GB setup apparently provides better bandwidth than a single 2x 32-bit 24 GB stick, which would be more expensive to manufacture anyway. Though ASRock's press material shows a 90 ns latency, which would be considered high by any modern standards.

ASRock HUDIMM standard

(Image credit: ASRock)

Following ASRock's announcement, Asus also chimed in with its own HUDMM showcase on a ROG Maximum Z890 Apex motherboard. A member of the R&D team took two regular 24 GB DDR5 RAM sticks and just taped half of the contact points, effectively disabling half of the ICs. Instead of showing 48 GB in the BIOS, these taped sticks showed only 24 GB.

The company didn't say whether it was partnering up with TeamGroup as well to add official HUDIMM support, but the fact that an engineer acknowledged it could signal something is in the works. If Asus hops on board the standard, an industry-wide push for this would be imminent, and we could genuinely see more affordable DDR5 soon. There is no word on availability or pricing from any side, however.

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Hassam Nasir
Hassam Nasir
Contributing Writer

Hassam Nasir is a die-hard hardware enthusiast with years of experience as a tech editor and writer, focusing on detailed CPU comparisons and general hardware news. When he’s not working, you’ll find him bending tubes for his ever-evolving custom water-loop gaming rig or benchmarking the latest CPUs and GPUs just for fun.

47 Comments Comment from the forums
  • Notton
    Half DIMM is such a dumb idea...
    So you turn your 128-bit mem bus into a 96-bit
    Say you're using 6000MT/s with 128-bit, that equals to 96GBps bandwidth
    Drop it to 96-bit and you're down to 72GBps
    Or, you could use 4800MT/s with 128-bit, and get 76.8GBps.

    And if you do upgrade the RAM on that, what are you going to do with the single stick of HUDIMM? Pair it with another HUDIMM? Congrats on dipping down to a 64-bit mem bus and running slower than DDR4-3200 in 128-bit.

    What's even funnier is that the HUDIMM shown by Asrock is running at 4800MT/s. It's even slower than the example I gave and only getting you 57.6GBps.
    That's the same bandwidth as DDR4-3600 in dual channel (128-bit).
    Reply
  • Findecanor
    Didn't the 'D' in "DIMM" already stand for them having dual 32-bit busses, because its predecessor ("SIMM") had only a single 32-bit bus ?

    "Half Dual" would then become a weird way to write "Single".

    I will call these "HUmbug DIMM" from now on :p
    Reply
  • Jokersona
    ...and how much will this save on costs? I can not imagine it will be a lot.
    Reply
  • usertests
    Jokersona said:
    ...and how much will this save on costs? I can not imagine it will be a lot.
    If you are targeting the same capacity, not much at all. This is a fiasco.
    Reply
  • torbjorn.lindgren
    Findecanor said:
    Didn't the 'D' in "DIMM" already stand for them having dual 32-bit busses, because its predecessor ("SIMM") had only a single 32-bit bus ?
    Nope!
    The Dual part comes from having different connectors on each sides of the PCB, as opposed to SIMM where the front and back connector are connected together. IE, they connect via dual connector edges vs SIMMs that has a single redundant set of edge connectors.

    The fact that early 30-pin SIMM had 8 or 9-bit (parity) wide buss shows that your interpretation isn't correct, the 72-pin 32-bit SIMMs came out later. And 30-pin SIMM was still very much being sold when the first DIMMs came out (similar to how DDR4 memory is still being sold).
    Reply
  • bit_user
    Notton said:
    Half DIMM is such a dumb idea...
    So you turn your 128-bit mem bus into a 96-bit
    That's only if you do a half DIMM + a full DIMM. I think the point of that example was to show that single-subchannel DIMMs provide a wider range of configuration options.

    Realistically, what's most interesting to manufacturers about this is the potential of having just a single 4 GB or 6 GB DIMM. Prior to this, there was no way to hit those capacities with DDR5. TBH, I'm not sure exactly how 8 GB DIMMs worked.

    Notton said:
    Or, you could use 4800MT/s with 128-bit, and get 76.8GBps.
    Costs more. Not everyone needs that much capacity. Although, to be honest, I think less than 16 GB isn't a great proposition for consumers. But, this provides a better way to hit 12 GB (i.e. 96-bit) than the old way of doing just a single 12 GB DIMM at 64-bit data width.

    Notton said:
    And if you do upgrade the RAM on that, what are you going to do with the single stick of HUDIMM? Pair it with another HUDIMM? Congrats on dipping down to a 64-bit mem bus and running slower than DDR4-3200 in 128-bit.
    Most boards sold still support 4 DIMMs. So, you could double-up the two HUDIMMs in the same channel and pair them with one or two regular DIMMs in the other channel, still giving you 96-bit data width.
    Reply
  • bit_user
    torbjorn.lindgren said:
    Findecanor said:
    Didn't the 'D' in "DIMM" already stand for them having dual 32-bit busses, because its predecessor ("SIMM") had only a single 32-bit bus ?
    Nope!
    The Dual part comes from having different connectors on each sides of the PCB, as opposed to SIMM where the front and back connector are connected together. IE, they connect via dual connector edges vs SIMMs that has a single redundant set of edge connectors.
    Well, here's how Wikipedia explains it:
    DIMMs (Dual In-line Memory Module) were a 1990s upgrade for SIMMs (Single In-line Memory Modules) as Intel P5-based Pentium processors began to gain market share. The Pentium had a 64-bit bus width, which would require 32-bit memory modules installed in matched pairs in order to populate the data bus. The processor would then access the two 32-bit SIMM modules in parallel.

    DIMMs were introduced to eliminate this disadvantage. The contacts on SIMMs on both sides are redundant, while DIMMs have separate electrical contacts on each side of the module. This allowed them to double the SIMMs 32-bit data path into a 64-bit data path.

    The name "DIMM" was chosen as an acronym for Dual In-line Memory Module symbolizing the split in the contacts of a SIMM into two independent rows.That sounds to me like @Findecanor is basically right. The Wikipedia description (which cites several sources I omitted) sounds like it's basically just combining two SIMMs onto one PCB.

    However, I don't know whether those SIMMs (or both sides of the early DIMMs) were truly independent channels. They could've been on the same address bus. It seems unlikely to me that CPUs of that vintage had multiple independent memory channels. I think that probably came with the move up from 64-bit to 128-bit memory interfaces.
    Reply
  • thestryker
    To me this is just an ominous sign as to how much longer the memory shortages are expected to go. Nobody would be developing this technology if the end was in sight.
    Reply
  • bit_user
    thestryker said:
    To me this is just an ominous sign as to how much longer the memory shortages are expected to go. Nobody would be developing this technology if the end was in sight.
    Yeah, I view it with mixed feelings. On the one hand, PC makers are desperate and I can understand their plight. On the other hand, we know too many of them offer products that exploit unwitting consumers with needlessly poor performance for the price.

    I guess I'd rather see this development than to have more PC makers go out of business and fewer options for consumers. Also, at least people who end up with these products will have the option to upgrade to full-width DIMMs, if/when the DRAM market returns to sanity.
    Reply
  • palladin9479
    This is dumb, just use a single DIMM and get the exact performance and size.
    Reply