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kriesel 2021-03-05 20:36

prime95 on Windows 10 gave mostly 2 cores/worker optimal, until reaching large exponents (~300M). But latency can be long compared to assignment expiration. See second attachment of [URL]https://www.mersenneforum.org/showpost.php?p=563304&postcount=11[/URL] for prime95/win10 exhaustive benchmark, for comparison to any ubuntu/mprime results to follow.

ewmayer 2021-03-05 21:27

[QUOTE=kriesel;573066]prime95 on Windows 10 gave mostly 2 cores/worker optimal, until reaching large exponents (~300M). But latency can be long compared to assignment expiration. See second attachment of [URL]https://www.mersenneforum.org/showpost.php?p=563304&postcount=11[/URL] for prime95/win10 exhaustive benchmark, for comparison to any ubuntu/mprime results to follow.[/QUOTE]

Thanks, though as usual I needed reading glasses. :)

My own rule of thumb for manycore-system runs is to go with whichever combo has the fewest #workers and yields at least 95% of the maximum total throughput, to keep completion times reasonable.

ewmayer 2021-05-01 21:43

Of possible interest to our UK readers, a cheap refurb [url=https://www.ebay.com/itm/Intel-Xeon-Phi-7250-68-Core-272-Thread-CPU-Knights-Landing-/224307986087]68C/272T 7250 KNL[/url].

Priced some RAM modules, going to hold off for now, but do occasional price-checks, posting links here for reference.

From the SuperMicro mobo manual:
[quote]The K1SPE has six (6) DIMM slots that can support 384 GB of Registered RDIMM up to 64 GB size and DDR4 2400 MHz speed, 1.20V SDRAM. See Chapter 5 for details.
(BIOS applicable settings related to memory: Memory Configurations -> Memory Map -> Channel Interleaving)
[/quote]
Recommended RAM modules: DDR4 1.2V-2400 is the fastest supported RAM frequency:
[code][b]DDR4 1.2V-2133[/b]:
GB-Per-DIMM Recommended Modules
8:
Samsung M393A1G40DB0-CPB [url=https://www.amazon.com/Samsung-Memory-M393A1G40DB0-CPB-DDR4-Registered/dp/B00NTBVQWS]$50[/url] per dimm
Hynix HMA41GR7AFR8N [url=https://www.amazon.com/Hynix-HMA41GR7AFR8N-TF-RAM-Module-electronics/dp/B01GSRRMAO]$44[/url] on Amzn
16:
Hynix HMA42GR7AFR4N-TF [url=https://www.amazon.com/1X16gb-PC4-17000-2133Mhz-Registered-HMA42GR7AFR4N-TF/dp/B01KWAK818]$56[/url] on Amzn
32:
Samsung M393A4K40BB0-CPB [url=https://www.amazon.com/Samsung-M393A4K40BB0-CPB-DDR4-2133-Memory-MEM-DR432L-SL01-ER21/dp/B00U6O78W8]$139[/url] on Amzn
Hynix HMA84GR7MFR4N-TF [url=https://www.amazon.com/Hynix-DDR4-2133-Server-Memory-HMA84GR7MFR4N-TF/dp/B00WSW6TEE]$139[/url] on Amzn

[b]DDR4 1.2V-2400:[/b]
GB-Per-DIMM Recommended Modules
8:
Samsung M393A1G40EB1-CRC [url=https://www.amazon.com/Supermicro-Certified-M393A1G40EB1-CRC-Samsung-DDR4-2400/dp/B01DTFVW6I]$50[/url] per dimm
Hynix HMA41GR7AFR4N-UH [url=https://www.amazon.com/Hynix-HMA41GR7AFR4N-UH-DDR4-2400-Server-Memory/dp/B01BCUS4CW]$40[/url] on Amzn
16:
Samsung M393A2K40BB1-CRC [url=https://www.amazon.com/Samusng-M393A2K40BB1-CRC-DDR4-2400-Server-Memory/dp/B01DTISRRC]$73[/url] on Amzn
Samsung M393A2K40CB1-CRC [url=https://www.amazon.com/Samsung-M393A2K40CB1-CRC-2400MHz-Memory-Module/dp/B078TZV5LN]$80[/url] on Amzn
Hynix HMA42GR7AFR4N-UH [url=https://www.amazon.com/Hynix-HMA42GR7AFR4N-UH-DDR4-2400-Server-Memory/dp/B01BCUS6QQ]$65[/url] on Amzn
Hynix HMA82GR7AFR8N-UH [url=https://www.amazon.com/Hynix-PC4-19200-2400MHZ-Model-HMA82GR7AFR8N-UH/dp/B01N6O511Z]$85[/url] on Amzn, but as low as $58 used [MicroMark had best price]
32:
Samsung M393A4K40BB1-CRC [url=https://www.amazon.com/Samsung-M393A4K40BB1-CRC-DDR4-2400-Server-Memory/dp/B01DTJ8EU6]$157[/url] on Amzn
Samsung M393A4K40CB1-CRC [url=https://www.amazon.com/M393A4K40CB1-CRC-SAMSUNG-PC4-2400T-R-Memory-Module/dp/B078V19STQ]$172[/url] on Amzn; this was the 1 module where the Sponsored-Ad top-placer in most of my DDG searches, Nemix.com, had the best price, [url=https://nemixram.com/samsung-32gb-m393a4k40cb1-crc-ddr4-2400-ecc-rdimm-2rx4-oem-compatible-memory/]$150[/url]
Hynix HMA84GR7AFR4N-UH $157 on Amzn
64:
Samsung M386A8K40BM1-CRC4Q [url=https://www.amazon.com/Samsung-PC4-19200-DDR4-2400MHz-Registered-M386A8K40BM1-CRC/dp/B01GSE85YO]$297[/url] on Amzn
Micron MTA72ASS8G72LZ-2G3B2 $298 on eBay, [url=https://www.amazon.com/Micron-64GB-DDR4-2400-LRDIMM-MTA72ASS8G72LZ-2G3B2/dp/B01KBDU852]$350[/url] on Amzn[/code]

Uncwilly 2021-05-01 23:34

[QUOTE=ewmayer;577391]Of possible interest to our UK readers, a cheap refurb 68C/272T 7250 KNL:[/QUOTE]That sold days ago.

kriesel 2021-05-07 10:53

[QUOTE=ewmayer;577391]Of possible interest to our UK readers, a cheap refurb [URL="https://www.ebay.com/itm/Intel-Xeon-Phi-7250-68-Core-272-Thread-CPU-Knights-Landing-/224307986087"]68C/272T 7250 KNL[/URL].
...
Recommended RAM modules: focus on DDR4 1.2V-2400, the fastest supported RAM frequency:[/QUOTE]That 7250 was the chip package only, requiring a compatible motherboard etc., so a possible upgrade path for a 7210 system. Such processors are quite commonly available on [URL="https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=xeon+phi+7250&_sacat=0"]eBay[/URL] etc.

It might be better to go with 2133 RAM. From [URL]https://www.mersenneforum.org/showpost.php?p=551372&postcount=8[/URL] (bold emphasis mine):[CODE]I found the following in the specification update:
"KNL25.Operating With DDR4-2400 Memory May Cause Unpredictable System Behavior
Problem:Operating the processor with DDR4 memory configured to operate at 2400 MT/s may cause unpredictable system behavior.
Implication:When the erratum occurs, the system will exhibit unpredictable system behavior.
Workaround:It is [B]possible[/B] for BIOS to contain a workaround for this erratum.
[B]Status:No Fix[/B]"[/CODE]Latest BIOS I found was 2.0a and does not address the preceding issue.

paulunderwood 2021-05-07 10:57

[QUOTE=kriesel;577854]... so a possible upgrade path for a 7210 system. [/QUOTE]

Scary number of pads on the "chip" -- would have to be carefully accurate putting into the socket.

kriesel 2021-05-07 15:03

1 Attachment(s)
From [URL]https://www.supermicro.com/manuals/superserver/mid-tower/MNL-1891.pdf:[/URL]
"These units are sold as complete systems with the motherboard, processor, and
heat sink assembly factory installed. These components are not user serviceable,
and the user should not attempt to remove or modify these components other than
adjustments specifically outlined in this manual. Making other adjustments to these
components risks damaging the system and voiding the system warranty."
There's a liquid cooling loop block mounted atop the package by two alignment pins,
4 Torx fasteners, and distinct tightening and loosening orders given on the block label.
Like torquing down a multicylinder engine head.
I've decided not to mess with mine.

ewmayer 2021-05-07 20:37

[QUOTE=kriesel;577854]It might be better to go with 2133 RAM.[/QUOTE]

I updated the current-prices table in my post above to add the officially supported 2133 DIMMs - as with 2400, the current sweet spot is at 16GB, one could buy 6 of those and thus max out the memory bandwidth to the resulting 96GB for around $360.


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