[QUOTE=axn;449598]
As a point of reference, my i3 skylake does about 28 Gd/d running 1st time LL on 4 (hyper)threads.[/QUOTE]
What is the core clock on the i3?

[url]http://ark.intel.com/products/93366/Intel-Core-i3-6098P-Processor-3M-Cache-3_60-GHz[/url]

[QUOTE=axn;450939][URL]http://ark.intel.com/products/93366/Intel-Core-i3-6098P-Processor-3M-Cache-3_60-GHz[/URL][/QUOTE]
Thanks! That is pretty impressive. ECC memory, even.

I confess that I went with the whole enchilada: i7 6700K, on an Asus Sabertooth Z170 Mk1. It has taken some effort to adjust to the Intel environment after 20+ years of AMD, and vast development by Intel since the Pentium Pro Overdrive chip: last Intel I ran.

I think I have CPU stability pretty well worked out. Early issues were actually glitches in my Win 7 transition. Beyond those, it seems that this chip is happy at 1.30-1.31 Vcore, though Auto in the BIOS puts it over 1.35 V.

Memory is 2 x 8MB, Corsair Vengeance LPX, rated 2133 MHz, 2400 XMP. It seems very well behaved on the XMP settings.

Default settings also put the CPU in Sync All Cores mode, which runs at Turbo speed on all the cores. I turn that off, so far. It runs hot, and I have not had time to evaluate stability. I am happy to have it produce good DCs at 4.0 GHz, while staying under 60° C. :smile:

EDIT: It does 58 G-D in 30 hours, which I take to be about 46 G-D/D, on 39M DCs.

If it's not too late, I would switch your RAM for something higher clocked. Your CPU is very much memory starved. Usually DDR4-3000 is reasonably priced compared to DDR-3200.

I've found that 4-core Skylake is memory starved above 3.3 GHz with dual channel DDR-2133: clocking faster for LL just makes more heat with only tiny performance increases. If you're getting 4.5 GHz out of your chip then DDR4-3000 will be about the sweet spot.

[QUOTE=kladner;450940]
I confess that I went with the whole enchilada: i7 6700K, on an Asus Sabertooth Z170 Mk1. It has taken some effort to adjust to the Intel environment after 20+ years of AMD, and vast development by Intel since the Pentium Pro Overdrive chip: last Intel I ran.
[/QUOTE]Oooh, that brings back memories. My PPro 225 is stashed away in the loft and was still working last time it was powered up.

[QUOTE=xilman;450945]Oooh, that brings back memories. My PPro 225 is stashed away in the loft and was still working last time it was powered up.[/QUOTE]
A single PPro ran just fine for me. However, when I attempted to run 2 of the overdrive version together it burned the board power connector. :picard:

[QUOTE=kladner;450947]A single PPro ran just fine for me. However, when I attempted to run 2 of the overdrive version together it burned the board power connector. :picard:[/QUOTE]Mine was a H-t-G PPro 200MHz device, suitably over-clocked. It was the 256k cache version; the two 512K chips I had available wouldn't run reliably at 225MHz. The extra cache helped at 200MHz over the 256K version but couldn't compete with the 225MHz, 256K chip.

I still have ~10 of those chips. I believe they are now worth USD 20 or so each as scrap Au. Those were the days.

[QUOTE=Mark Rose;450943]If it's not too late, I would switch your RAM for something higher clocked. Your CPU is very much memory starved. Usually DDR4-3000 is reasonably priced compared to DDR-3200.

I've found that 4-core Skylake is memory starved above 3.3 GHz with dual channel DDR-2133: clocking faster for LL just makes more heat with only tiny performance increases. If you're getting 4.5 GHz out of your chip then DDR4-3000 will be about the sweet spot.[/QUOTE]
I certainly noticed the difference when I switch it from 2133 to 2400 MHz. I will have to look at the receipts.

[QUOTE=Mark Rose;450943]If it's not too late, I would switch your RAM for something higher clocked. Your CPU is very much memory starved. Usually DDR4-3000 is reasonably priced compared to DDR-3200.

I've found that 4-core Skylake is memory starved above 3.3 GHz with dual channel DDR-2133: clocking faster for LL just makes more heat with only tiny performance increases. If you're getting 4.5 GHz out of your chip then DDR4-3000 will be about the sweet spot.[/QUOTE]

Generally agreed with the above. I run my quad Skylakes at 4.2 GHz and try to get as fast ram I can in them, but also finding that ram compatibility isn't as great as it could be once you reach around 3000+ speeds. Also note dual rank ram can offer significant performance over single rank in the same speed/setting configuration. Where ram limited, I found dual rank gives about 20% more performance. Unfortunately it is hard to find this info listed, but as a rule of thumb 4GB DDR4 modules are single rank, 8GB may be single or dual, with higher performing ones generally moving towards single.

Note my observations apply to the case of one core per worker as that is essentially my use case with LLR. I've not really looked into multiple cores per worker.

[QUOTE=mackerel;450981]Generally agreed with the above. I run my quad Skylakes at 4.2 GHz and try to get as fast ram I can in them, but also finding that ram compatibility isn't as great as it could be once you reach around 3000+ speeds. Also note dual rank ram can offer significant performance over single rank in the same speed/setting configuration. Where ram limited, I found dual rank gives about 20% more performance. Unfortunately it is hard to find this info listed, but as a rule of thumb 4GB DDR4 modules are single rank, 8GB may be single or dual, with higher performing ones generally moving towards single.

Note my observations apply to the case of one core per worker as that is essentially my use case with LLR. I've not really looked into multiple cores per worker.[/QUOTE]

Good to know. My Skylake systems are all running 2 x 16GB of G.SKILL Aegis DDR4-2133 F4-2133C15D-32GIS. From what I can tell, those are dual rank modules.

[QUOTE=Mark Rose;450990]Good to know. My Skylake systems are all running 2 x 16GB of G.SKILL Aegis DDR4-2133 F4-2133C15D-32GIS. From what I can tell, those are dual rank modules.[/QUOTE]
I take it that you are running this somewhat faster than the label suggests?

EDIT: Or maybe not, on re-reading. I have seen Corsair 3000 modules for about what I paid for nominal 2133. As near as I can tell from the returns policy as stated online, I can still exchange the ones I have. It does seem that more of the parts at those speeds are 1.35 V, instead of 1.2.

This really makes me wonder if the RAM I have will run reliably above DDR4-2400. However, getting parts which are rated for the speed, and have specified timings, has a lot of appeal.