HP Z8 G4 can use optane dimm's?

[miloman]

Hi, I have a Z8 G4 with 2 x 6254's, 192GB RAM and a RTX A5000. Is anybody using optane memory module? Are they a performance upgrade?

[BeemerBiker]

IMHO Optane memory was good when systems had mechanical hard drives.  If you removed the 16mb Optane and substituted a 1tb NVMe SSD then there is no mechanical drive to speed up.  That is what I did.

Is Optane memory dead? Looks like it for new systems

[DGroves]

the HP Z8 G4 is available with two different motherboards

one for normal consumer Intel based cpu's and one for the Xenon series cpu's

only the xenon based motherboard supports Optane when using specific cpu's that have optane support

Intel® Optane™ PMem can be used as main memory on select HP Z6 G4 and Z8 G4 workstations with Intel® Xeon® 8200, 6200, 5200 and select 4200 series processors.

optane memory will be expensive........and unless you need or can use the specific features of it is not cost effective for most users

in a nutshell

While both Optane memory and DDR4 are types of computer memory, Optane is designed to bridge the gap between traditional RAM (like DDR4) and storage devices like SSDs, offering faster access times than a standard hard drive but with slightly slower speeds compared to DDR4 RAM, while also retaining data even when the computer is powered off, making it "persistent" memory; essentially, DDR4 is significantly faster for typical RAM operations but loses data when the computer shuts down, whereas Optane is slower but retains data persistently. 

Key Differences: 

• Speed:

  DDR4 generally has significantly faster access times than Optane memory, making it ideal for applications requiring rapid data transfer like gaming or video editing. 
• Persistence:

  Optane memory retains data even when the computer is turned off, unlike DDR4 which loses data upon power loss. 
• Usage:

  DDR4 is primarily used as the main system RAM, while Optane is often used to accelerate the performance of frequently accessed data from slower storage devices like hard drives. 

[miloman]

Thanks, interesting read! I agree that it is dead, but maybe it could still help teh performance of the g4's.

I have a laptop with ddr5 and it feels so much faster than ddr4....

On the Z8 I also only use nvme ssd's in the 2 extra cards.

[miloman]

I wasn't aware of the 2 type of motherboards for the Z8 G4, but mine has the 6254 now. I don't think it will bring a lot, but 2 128GB module will set me back about 100 euro, so I will just go ahead and try them. 

Intriguing that will work alongside the normal RAM's, I did not see any seating instruction mentioning these optane modules.

Downside is that they run @ 2666MHz, instead of 2933 MHz my DDR4 modules have now.

[SDH]

A few added details based on our experience here:

1. DGroves accidentally mixed-up info on the Z4 G4 with the Z8 G4. It is the Z4 G4 that has two different motherboards, one officially for the Xeon and the other officially for the Core Intel processors (plus other physical differences). Neither of those Z4 G4 motherboards can run Optane memory. All 3 of the top ZX G4 workstations can run the Optane SSDs that HP lists in their respective QuickSpec sections.

2. Faster memory cannot make a slower processor run faster. A slower processor will slow down faster memory to its own speed. Memory and processor(s) cannot run faster than the top speed the workstation is rated for (2933 MT/s for the ZX G4 family). Your Xeon Gold 6254 processors are also rated by Intel to max out at 2933 MT/s. I think it would be a good idea to get two more memory sticks identical to what you currently have, rather than Optane memory.

3. There is a good HP White Paper document on Optane memory use and seating in the Z6 G4 & Z8 G4 (referenced in the Z8 G4 QuickSpecs under the Optane memory section) that does not link properly and can be hard to find. A copy is attached below as a PDF for your reference, but I agree technology has moved on from that.

4. By the way... quality M.2 NVMe4 SSDs run faster in the ZX G4 generation of workstations despite the PCIe slot technology in those topping out at NVMe3. Same thing for the ZX40 family of HP workstations. That's what I'd recommend investing in too if you're not already running good NVMe3 M.2 SSD(s). I have not tested a NVMe5 M.2 SSD in those yet.

See attachment below:

[miloman]

Wow, that is a great document, many thanks! Will dive into it tomorrow!

I already have 192GB of RAM, so I don't need an upgrade. I was just curious what these modules would bring.

I the past I even got the VROC update key to see what that would bring. But VRON needs specific types of NMVE ssd's which I did not manage to get (maybe eassier nowadays).

I am running a Samsung SSD 970 EVO Plus as a system drive. And 4 nvme's in RAID0 (no harm if I lose that data, it's just a quick work environmnet for video editing).

[miloman]

The modules I mean go into the DIMM slots, so like memory modules. The one's I ordered are 128GB each, and I am looking at configuring them in 'Storage mode'. Curious to see how fast this storage is.

From the documentation I see it cannot be configured as a boot-device, which is a pitty (was hoping for a fast-er boot device). And I hope 2 DCPMM modules will work, looking at the diagram on page 22.

Nice experiment (I hope) 😁

[miloman]

I received 2 DCPMM's today, and did the first tests in storage mode, Very fast disks, around 2.4GB/s when copying from a striped 4x1TB NVME SSD. Although at the end it slows down...

Unfortunately I cannot stripe these 128GB modules into 2 256GB disk... Maybe that's because I installed both modules in proc 0 slots (as advised in the pdf that ... shared).

I will have a look at memory mode and 'app direct' mode. I think the application needs specific coding to make use of the 'app direct' mode, so need to search.

So far not very useful stuff as we already concluded, as nvme ssd's are even faster.