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1) Message boards : Generalized Fermat Prime Search : GFN Prime Discoveries (Message 123249)
Posted 11 hours ago by Profile Michael GoetzProject donor
You decided not worth time or effort to upshift exponents anymore?


I didn't really like the way it looked, and it took more characters. That's significant because there's a hard limit to the number of characters in each post, so I can get more primes in a single post by using "^" instead of "[ sup ] ... [ /sup ]".
2) Message boards : Generalized Fermat Prime Search : GFN Prime Discoveries (Message 123245)
Posted 13 hours ago by Profile Michael GoetzProject donor
We've found two n=15 (32768) primes!


On 9 Dec 2018 5:50:11, the 263,291 digit prime 108386190^32768+1 was found by Kellen using the OCL2 (combined) app.

The double checker of this task was LCB001 on 9 Dec 2018 10:43:34 using the OCL2 (combined) app.


On 9 Dec 2018 11:35:07, the 263,293 digit prime 108404954^32768+1 was found by Kellen using the OCL2 (combined) app.

The double checker of this task was Adrian Schori on 9 Dec 2018 12:29:56 using the OCL2 (combined) app.


Congratulations!
3) Message boards : Generalized Fermat Prime Search : GFN Prime Discoveries (Message 123229)
Posted 1 day ago by Profile Michael GoetzProject donor
We've found an n=16 (65536) prime and two n=15 (32768) primes!


On 7 Dec 2018 18:27:55, the 501,641 digit prime 45126534^65536+1 was found by Jason using the OCL2 (combined) app.

The double checker of this task was CStephenZh on 7 Dec 2018 21:14:25 using the OCL2 (combined) app.


On 8 Dec 2018 4:45:27, the 263,280 digit prime 108303180^32768+1 was found by Kellen using the OCL2 (combined) app.

Double checker information TBA.


On 8 Dec 2018 5:52:26, the 263,280 digit prime 108307338^32768+1 was found by Kellen using the OCL2 (combined) app.

The double checker of this task was SkyHighWeFly on 8 Dec 2018 6:38:01 using the OCL2 (combined) app.


Congratulations!
4) Message boards : Number crunching : Primegrid and BOINC thoughts on the i9-9900k vs i7-9700k (Message 123228)
Posted 1 day ago by Profile Michael GoetzProject donor
My old home pc – i7-2600K died recently (or its mobo did, doesn't really matter), so I had to upgrade. And I decided to go full latest route and bought the i7-9700K.

I can confirm that it's way too power-hungry on the full load. If I understood that before, I think I would have gone with i7-8700K now.

I believe, I have a bit better cooling than Honza? Thermalright true spirit 120m. Power supply is 750 watt. However, in my case the culprit is the UPS that i have this machine on – apc es 525. I believe it's about 500 watt, but I'm looking at specs right now and not understanding the VA metric.

Everything was mostly fine when I tried PPS LLR first on 2 threads, then on 4. The temperature of the cores running LLR (and looks like the threads were locking quite well into the cores without the affinity push) went to about 80 deg C, the rest being idle-ish at about 40-50. HWMonitor was showing about 100W package power with 120W peak.

But when I tried running on all cores (2 instances of 4-threaded PPS LLR), UPS went into the screeming red mode, crying about an overload and shutting down power (I assume – the pc went dark), while there was a distinctive smell of electronics getting too hot that really scared me (frying a very expensive new PC right away especially after some complications that I had along the way would be... ugh, don't want to talk about it). It happened too fast and I wasn't looking at the temps and the power draw. The GPU was also crunching at that point.

I want to run more tests, but I'm kinda feeling too wary right now. Maybe I'll try drawing power right from the wall outlet without the UPS too. But later. Baby steps for now.


If you search, you may find some tales I told a few years ago about new-fangled power supplies (i.e., EU-load factor regulation compliant) and the way most UPS's interact with them. Short version, only a few consumer-gradel UPS's produce true sine-wave outputs, and stepped-output UPS's don't get along well with newer power supplies. Well before you get near the power limit of the UPS the combination of the high load factor power supply (or maybe low load factor, I forget) and the stepped sinewave interact in such a way that it overloads the UPS.

You need to make sure your UPS produces a true sine wave. Hint: as of a few years ago, APC sold exactly zero consumer UPS devices with a sine wave output. Their office UPS's have real sinewave outputs, but they cost 2 or 3 times as much. It's possible that's not longer true, but at the time I had to switch to a Cyperpower UPS to get one that would work with a new power supply at more than about 40% capacity.
5) Message boards : Aggie The Pew message board (Message 123209)
Posted 2 days ago by Profile Michael GoetzProject donor
Before you start snickering derisively, let me at least note that this was all on CPU:



Gary


Isn't that a reason to snicker even more? :)
6) Message boards : Generalized Fermat Prime Search : GFN Prime Discoveries (Message 123205)
Posted 2 days ago by Profile Michael GoetzProject donor
We've found another n=15 (32768) prime!

On 7 Dec 2018 5:50:19, the 263,269 digit prime 108223996^32768+1 was found by Kellen using the OCL2 (combined) app.

The double checker of this task was Adrian Schori on 7 Dec 2018 6:08:15 using the OCL2 (combined) app.

Congratulations!
7) Message boards : Number crunching : Primegrid and BOINC thoughts on the i9-9900k vs i7-9700k (Message 123204)
Posted 2 days ago by Profile Michael GoetzProject donor
Running 8 instances of SGS crashes the box immediatelly, I guess hitting currents limit or limit of mainboard or 350W power. Yeah, only 350W - but the box is only CPU, RAM, single M.2 SSD and no other drives, GPU or any other cards.


Remember that nothing related to power is 100% efficient and everything on the motherboard that has a heatsink is drawing more than a little power. The ram is drawing a fair amount of power as well. I would, at least as an experiment, put a 500 or even 600 watt power supply in there.
8) Message boards : Generalized Fermat Prime Search : GFN Prime Discoveries (Message 123195)
Posted 3 days ago by Profile Michael GoetzProject donor
We've found three n=15 (32768) primes!


On 6 Dec 2018 6:06:42, the 263,258 digit prime 108136908^32768+1 was found by Kellen using the OCL2 (combined) app.

The double checker of this task was Ruud van der Kroef on 6 Dec 2018 14:36:22 using the OCL2 (combined) app.


On 6 Dec 2018 8:41:26, the 263,259 digit prime 108149056^32768+1 was found by Kellen using the OCL2 (combined) app.

The double checker of this task was LCB001 on 6 Dec 2018 13:50:57 using the OCL2 (combined) app.


On 6 Dec 2018 19:09:55, the 263,266 digit prime 108197446^32768+1 was found by Kellen using the OCL2 (combined) app.

The double checker of this task was Johny on 6 Dec 2018 19:58:04 using the OCL2 (combined) app.


Congratulations!
9) Message boards : Sieving : New automated manual sieving system (Message 123184)
Posted 3 days ago by Profile Michael GoetzProject donor
Is the automated manual sieving system only for GPUs?


At this moment in time, yes, it's only GPUs, but that'e because right now only GFN sieving is available. Those are GPU only.

Is the memory minimum 1.5G like it is for BOINC GPU projects?


I'm pretty sure it's not, because I don't think we've ever talked about memory requirements for any of the manual sieving programs. I don't think anyone's ever had a problem with lack of video memory, even going way back when GPUs had much less memory

Is there a way to get PSA credit with CPU-only?


Yes, with PRPNet. Check out the Project Staging Area forum (the forum right above this "Sieving" forum.)
10) Message boards : Number crunching : Winter Solstice Challenge (Message 123182)
Posted 3 days ago by Profile Michael GoetzProject donor
hi

You say that GFN-21 tasks are currently averagiing over 11 days: whiich of course implies an "average" CPU will not reach the scoreboard for this challenge.


First of all, everyone's computer is different, so just go and test it yourself. You don't need to run an actual BOINC task. Just get the genefer program and run it from the command line. After a short while it will tell you how long it will take to run, and its estimates are *VERY* accurate. If it's estimating less than 240 hours, it will be able to complete the task within the challenge. Be sure to test in the same configuration as you'll be actually be running during the challenge, since it matters what else is running.

If you want a general rule of thumb for what should work:

Divide CPUs into two classes: Those that have at least AVX, and those that do not. If your CPU does not have AVX, it can't use multi-threading, and is also probably an old and slow CPU, and I'm guessing it won't make it.

If it has AVX (or FMA), and you use multithreading (remember, it's -nt #, not -t #), and it's not a terribly slow computer, I'm guessing you can get at least one task done. My 4 core dsektop Haswell can do a GFN21 in about 38 hours using 4 cores and about 44 hours using 3 cores. Obviously, running on a 2 core machine will take longer, as will running on a laptop or other low power CPU. I think AMD CPUs with AVX do count as having AVX, so they should be able to use multi-threading, but per-core they will be a lot slower than Intel.

Bottom line: AVX or better and using multithreading: very likely. Otherwise, probably not.

P.S. Multi-threading is only usable with GFN-21, so there are not a lot of people who have real experience using it in a live environment.


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