Fanless Xeon-W build.

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KarelG

Member
Jan 29, 2020
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Hello,

after months of thinking I've decided in Jan/Feb this year (2020) to rebuild my workstation around Xeon W chip. The motivation for this was:

- modest multi-threaded needs.
- spike single-threaded needs. E.g. as fast as possible ST perf. for short amount of time.
- quite high RAM needs.
- ECC RAM supported/verified by vendor.

At the time of decision I've used venerable Xeon E5-2620 + 64GB RAM in X9SRA board. Average CPU consumption was less than 10%, RAM consumption was more than 60-70%. As usual I'd like to build workstation which will be at least twice as fast as previous one. With 64GB RAM I've already been past update to 128GB for some time. I've also preferred to use non-China build motherboard. From requirements I've settled on:

- kontron/fujitsu D3598-B13 board
- intel Xeon W-2295
- 256GB RAM (4x64 LRDIMM)
- Zalman TNN 500 AF case -- inherited from previous workstation build
- Nvidia NVS 300 -- inherited from previous workstation build
- 2x Crucial MX500 2TB, 1x Crucial MX500 1TB -- inherited from previous workstation build
- PSU: SilverStone NJ450-SXL

Unfortunately due to W-2295 not being available in EU for several months I've needed to downgrade my plan to W-2265 which actually provides quite nice perf/price ratio upgrade. At the time I've recomputed performance/price ratios of W-2235 (6 core like past E5-2620), W-2255, W-2265, W-2295 and using performance figures from geekbench and balancing based on my ST/MT need I've found out W-2265 to be quite good. In fact for MT benchmark and based on Geekbench numbers it provided the best perf/price ratio of all those chips. Also Geekbench perf. different between W-2265 and W-2295 was not so big for the price needed to pay. The only thing which hurts me is that W-2295 would be way much better in power consumption when running in 12cores/24threads as W-2265, but man can't have everything.

It took me few months between board purchase and CPU/ram purchase. I've been especially deciding on RAM used. Discussed with Kontron/Rutronik24 and settled on Samsung lrdimms. Anyway, the assembly was not panacea as the board comes with old R1.8.0 BIOS (although Kontron engineer claimed the board will support W-2295) hence it was not possible to post with W-2265. I've thought the problem is with RAM, hence purchased Fujitsu/Kontron tested 8GB RDIMM Samsung RAM and no way. At the end I've purchased W-2123 from ebay, put it there and indeed, BIOS was R1.8.0 hence not supporting W-22xx CPUs. Flashed 1.20.0 then 1.22.0, exchanged CPU and everything was fine. Exchanged RAM and so now I'm on 64GB RAM in one stick with another stick (64GB) on the road to me. Based on uncertainty with RAM I've decided to upgrade RAM piece by piece since if something's not working, I'll need to sell on ebay with a loss.

Some why not answers:

- why not AMD 3xxxx -- excellent CPU, in fact I've tested this by building another testing workstation build. Price/perf fantastic, but max 128GB ECC UDIMM. I'd also need to modify retention mechanism to fit my case which used 2011 bracket which turns out to be compatible with 2066.

- why not AMD TR -- too big CPU and too way over case TDP limit.

- why not AMD Epyc (7282 etc.) -- excellent CPU, good TDP, but lower than Xeon W single-threaded performance. Also a need to modify retention mechanism. Big CPU surface and boards only with horizontal DIMM slots which would not be good to put into my case. See photo below. Ditto for latest 7Fxx line but this is way more close.

- why not fans. A long time already I hate noisy computers. Sitting next to fan-based computer get always up to my nerves after few hours of work. In the past when computers were noisy I solved that by using notebook which was more silent. Then I've discovered TNN 500 AF and was lost. Anyway, as I build also other computers for different purposes than my main workstation I'm from time to time evaluating current state of fans technology. Last build was my testing build of Ryzen 3600x. Used noctua nh-u12a for cpu cooler and nf-s12a pwm fans as a replacement for fractal designs case fans. Case is small fractal design define. Using this setup is possible for me over day, especially when I do not push it. Fans are on 300rpms and this way, over day, the setup is *silent*. I don't hear it at all. But when I push it, then fans ups their rotation speed and become noticable. Also in night, even this silent configuration is a no go. Note, I'm living/working in quite silent area and I love silent night hacking sessions. Conclusion: having Epyc or TR with noctuas top class cooler/fan is still a no go for me, since those CPU requires more intensive cooling than Ryzen 3600x hence fans will be on higher rpm than 300 hence not-tolerable by me especially not for night and/or longer period of time. By the way, my definition of *silent* machine is this: machine is silent if during the time it is being switched off, you do not notice any difference in produced noise. So basically there is no difference between noice produced by machine running and machine switched off. Although this is highly depending on usage environment (high noise flat in city near to high-way versus silent house in fields) it's still the best def for me.
Another possibility may be to have small rack with noctua's based epyc/tr box somewhere in closet and work on it remotely from my room. However for this time, I've decided on updating Zalman as workstation is still more convenient to use than workstation/client + server for work combo.

Something about case:

TNN 500 AF. Purchased IIRC 14-15 years ago. It stays with me while housing AMD A64 Winchester 1.8GHz + 1GB RAM, Intel Q6600 + 6GB RAM and finally Intel E5-2620 + 64GB RAM. During the time it lost its PSU, so I'm using as efficient as possible fanless PSU just put on the bottom of the case. Just laying there even not screwed to the side of the case. Zalman recommends to put CPU only with 100W TDP limit into it, otherwise to employ slow moving 12cm case fan. Also with higher than 100W TDP limit, so called termal blocks are needed to be installed at the back of board to transfer heat from CPU power cascade down to case. Honestly I've not done this time anything like that. I've purchased semi-industrial Kontron board and hope power cascade will hold my work's cpu pressures well. We will see.

Security note: due to Intel's bad CPU security, the CPU is always run with HT disabled which I hoped will lower a bit power requirements.

Power measurement:

CPU: nearly idle: <16W with <10% CPU use running on 1.2GHz all cores (desktop, firefox with a lot of tabs, thunderbird, etc.) -- this is how it's working as a daily driver. IMHO 99% of time is like this with occasion spikes over 20W.
CPU: max: <160W with 100% CPU use running on 4.3GHz all cores by make -j14 on LLVM code base

Temperatures:

CPU: nearly idle (see above): 7-8C added to room temperature (22-26C) resulted in (29-34C)
CPU: max: (LLVM code base build with make -j12): up to 72-73C and then throttling. E.g. all cores go from 4.3GHz to 1.2GHz for a second or so, temperature immediately drops from >70C to around 50C. Actually around 50C looks like a temperature of the CPU block in this warm case and 20C are jumps of temperature when all cores kick in. This also happen when case is cold and I just start make -j12. The temp immediately goes from idle temp to idle + ~20C. E.g. 50C. And this happen during first 1-3 seconds of make -j12. How is throttling intensive depends on temp. before start of make -j12. Here is comparison table with temp. before build and time to build LLVM 10:
29C -> 9m38s
37C -> 10m32s
41C -> 11m50s
I've also tried to find temperature stable configuration where by stable I mean w/o causing throttling and it looks like this is when running just 6 cores and power consumption at this time shows slightly below 100W which looks like Zalman was right about suggesting just 100W operation in fanless mode.

Testing done on Ubuntu 18.04, power reqs. reported by s-tui utility.

Future modifications:
- slowly update to targeted 256GB RAM
- perhaps attach PSU to the side of the case to better cool it and more importantly to make less heat inside the case.

Picture of board in case is here: kontron_zalman.jpg
 
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Boris

Member
May 16, 2015
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Power measurement:
CPU: nearly idle: <16W with <10% CPU use running on 1.2GHz all cores (desktop, firefox with a lot of tabs, thunderbird, etc.) -- this is how it's working as a daily driver. IMHO 99% of time is like this with occasion spikes over 20W.
CPU: max: <160W with 100% CPU use running on 4.3GHz all cores by make -j14 on LLVM code base
Thank you for posting, it was interesting to read.
Which temps you get at idle and 100% load?