New HUDIMM DDR5 Standard Promises Cheaper Memory, But Testing Shows It Slashes Bandwidth in Half

Intel is working with partners to release a cost-effective DDR5 memory design called HUDIMM, but it will lead to much lower performance.

DDR5 HUDIMM Memory May Look Great For Budget Builders, But The Performance Impact Is So Huge, It Makes DDR4 Look Better

Last week, Intel introduced a new DDR5 memory standard, along with its partners, called HUDIMM. The HUDIMM standard stands for Half-UDIMM & what it does is switch from two 32-bit channels that are featured on normal memory modules to just one 32-bit channel. This should allow memory makers to build cost-effective memory by populating half of the banks on a module.

The first HUDIMM memory is expected to come in 8 GB and 12 GB flavors. PC builders will be able to mix and match the modules with standard UDIMM and HUDIMM kits with the same or different capacities.

But while the memory standard sounded decent for budget builders, giving them some sort of cost-effective option in today's memory-constrained world, the reality is that HUDIMM has a severe drawback.

In performance tests conducted by HKEPC with the help of ASUS, a standard UDIMM was converted to a HUDIMM module by shielding half of the banks. This converted the UDIMM from 2x32-bit channels to 1x32-bit channels. Various configurations were tested and evaluated in the AIDA64 cache and memory benchmark. The results are stated below.

• [8GB - 1 x 32-bit Single Channel] 1 DIMM (Disabled) - 7200 MT/s
  32,447 MB/s Read, 25,195 MB/s Write, 26,894 MB/s Copy, 87.7ns
• [16GB - 2 x 32-bit Single Channel] 1 DIMM (Unmasked) - 7200 MT/s
  58,913 MB/s Read, 48,800 MB/s Write, 52,648 MB/s Copy, 85.7ns

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First up, we have a 16 GB UDIMM converted into an 8 GB HUDIMM. The standard 16 GB UDIMM offered almost 60 GB/s of bandwidth, while the converted 8 GB UDIMM dropped the bandwidth to just 30 GB/s. This test featured a single-channel configuration.

The same is the case with the 32 GB UDIMM, which was converted into a 16 GB UDIMM. A single 32 GB UDIMM offered over 100 GB/s bandwidth, and once again, when converted to a 16 GB HUDIMM, the total bandwidth dropped below 60 GB/s. This test featured a dual-channel configuration.

• [16GB - 1 x 32-bit Dual Channel] 2 DIMM (Disabled) - 7200 MT/s
  58,928 MB/s Read, 48,461 MB/s Write, 51,473 MB/s Copy, 86.5ns
• [32GB - 2 x 32-bit Dual Channel] 2 DIMM (Unmasked) - 7200 MT/s
  106.02 GB/s Read, 93,235 MB/s Write, 97,522 MB/s Copy, 86.4ns

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Switching off the regular channels didn't net a loss in latency as that was stable in the 85-87ns range, but this goes on to show that the performance loss will be far more significant, and wasn't explained or highlighted well enough during the introduction of the HUDIMM standard.

So, what this means for PC gamers and PC builders is that while the HUDIMM DDR5 memory modules will come at a lower cost, you will also see much lower performance. In fact, running a single UDIMM in single-channel mode will be better than running two HUDIMMs in dual-channel mode, as pointed out by HKEPC, and that might just be a deal breaker.

Now the question is, will the HUDIMM DDR5 memory modules also cost half as much as standard UDIMM modules based on their performance?

News Source: HKEPC

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