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[guru]

Doh! Found this in the logs from my i7-3960X

[Tue Feb 10 16:36:23 2015]
Iteration: 6934673/15990667, Possible error: round off (0.4375) > 0.40
Continuing from last save file.
[Tue Feb 10 17:00:31 2015]
Disregard last error. Result is reproducible and thus not a hardware problem.
For added safety, redoing iteration using a slower, more reliable method.
Continuing from last save file.

I still say there is something wonky with the AVX code. I only have crashes on the AVX enabled systems and all of them are running stock speeds. I could accept one or two systems but 4 of 7 systems is a lot. I have non AVX systems that are overclocked and no issues at all. Only one of the systems affected is running linux. The others are running windows 7 x64.

[pinhodecarlos]

I already had those errors when I was using Prime95 on dual core server (linux mprime).
When I shared at mersenneforum that error Prime95 told me not to worry. Few weeks after when someone found a bug on the software I decided to retest all candidates in a another CPU and OS and I got different residues. I shared this on mersenneforum but didn't get any reply.

[guru]

I added ~ 25 AVX systems yesterday and three have already crashed.

[tim]

Guru, were they overclocked much? The only stability issues I've had with prime95 client were hardware related. But I don't overclock either (don't slap me too hard).

Thanks for posting the comparisons of cpus. I noticed i5-4690K didn't have any data, did it not appear properly in the post? My rookie interpretation of the posted data makes me think on a per core basis the i7-4770K and the E5-2697V2 are roughly the same in production. Is that how you read it?

I appreciate you taking the time to hash this out. I hope it's not affecting your day job.

[guru]

Nope these systems are in 1U racks and used only as computing systems. 24/7 stability vs high performance. Many of my AVX systems have the same motherboards and very similar memory. It is possible it is not related directly to the CPU. I have noticed turning off Turbo helps. I will do more testing with a few specific trouble systems and try to isolate the issue.

I don't have a 4690K for testing so I just put the specs to compare it to what i have. If someone else has one that can provide the data that would be good. I have more results to share and I may just put it into a spreadsheet and upload it.

My rookie interpretation of the posted data makes me think on a per core basis the i7-4770K and the E5-2697V2 are roughly the same in production.

It depends on the FFT size. The 4770K is faster at 1024K FFT size but most of what I have seen running are 2560K which puts the 2697V2 about 45% faster than the 4770K

This doesn't directly relate to my day job but everything I learn from it does apply. Knowledge like this doesn't come in a book or a lecture.

[pinhodecarlos]

Can I suggest running SRBASE project instead of SOB? With such power on SOB with such errors it will cost SOB more doublecheck effort in the future.
http://srbase.myfirewall.org/sr5/index.php

The invitation code for creating new accounts is pillepalle

[guru]

Can I suggest running SRBASE project instead of SOB? With such power on SOB with such errors it will cost SOB more doublecheck effort in the future.
http://srbase.myfirewall.org/sr5/index.php

The invitation code for creating new accounts is pillepalle

Does it support proxy, Linux, and command line?

[guru]

Here are the power number comparing the 2700K to the 4770K. Both are very similar and basic systems.

2700K
850W power supply
Intel SSD
2 x 4GB 1600 Memory
DVD
Intel DZ68BC motherboard
OpenSuse 13.1
HT off
4 Cores
Turbo disabled

4770K
610W power supply
Intel SSD
2 x 4 1600 Memory
DVD
Asus Z87-Expert motherboard
Windows 8
HT off
4 Cores
Turbo disabled

             Idle   SOB   TT small      TT blend       TT large      OGR   RC5
2700k        42     129   124           122            129           104   104
4770K        66     142   142           129            140           97     95

Take away: 4770K with avx2 is faster but requires more power to do it(nothing for free). I suspect the extra power is the stress on the memory system due to the increased throughput. FFM3 instructions use more power than AVX. Makes sense given the larger registers.

99% sure the difference in idle power has to do with the c-states in the bios. I believe they are disabled on the 4770K(something we normally do for testing) but enabled on the 2700K after the last bios update. This would not affect the power usage under load.