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1) Message boards : Generalized Cullen/Woodall prime search : GCW-Sieve is ending May 1st (Message 128408)
Posted 25 days ago by Profile Rafael

GCW Sieve is shutting down May 1st

Need just a bit more credit for a badge? WUProp hours? Best hurry up and get it now.

Oof, that's gonna be tight. I need ~4.5M to reach Jade, but by my calculations, I'll only make it to 4M. I might need to create extra PCs out of thin air...
2) Message boards : Problems and Help : nVidia NVS 310 gpu (Message 128399)
Posted 25 days ago by Profile Rafael
I've got this in an OLD system; is it worth using?

I mean, I used to PPS Sieve with a Radeon HD 4450, it would take me 20~22h crunching non-stop to get a WU done, and I imagine you would be in a similar cenario with that GPU of yours.

In terms of power efficiency, no, it's not worth at all. But if you really, REALLY want that extra bit of crunching power (and assuming you can get it to work, ofc), I suppose you could try it.
3) Message boards : Seventeen or Bust : The SoB Double Check has begun (Message 128229)
Posted 31 days ago by Profile Rafael
How come running SOB on 2 cores and starting in the past few days 3 cores on a Intel(R) Core(TM) i5-6600 CPU @ 3.30GHz with 16GB RAM, running Windows 10 Core x64 Edition and I am about 80% of the time 1st.
Are all the big guns away ?

Multithreading more than halves compute time on a CPU like yours, and because you have to manually go out of your way to enable it, the few that do have a huge advantage over those that don't.

Additionally, people that aren't closely looking at their tasks usually stockpile a whole bunch of tasks, so it ends up being easier for people downloading one at a time to be 1st.
4) Message boards : Generalized Fermat Prime Search : First *megaprime* in GFN16 (or GFN15) series (Message 127559)
Posted 52 days ago by Profile Rafael
I wonder how many peoples with significant computing power (e.g. >20 cores total) are interested in this project. Required computing power still look big, and I need to make some estimations about optimal sieving ratio.

Currently we have 190'800 candidates to test. This number is decreasing slowly thanks to GPU sieving at high area, but I'm still working on the problem of sieving in middle area between 0.008P (current CPU sieving progress) and 1.815P (start of GPU sieving). I finally wrote a GPU-assisted sieving program, it's working fine in test environment (software OpenCL) but crashes NVIDIA drivers/compiler... So I still have work to do, may be try other versions of drivers... or just find an AMD card :)

Wouldn't it be easier to Run a couple P on the GPU and remove those candidates to then have less stuff to sieve on the middle area? If I understand correctly, it doesn't matter how many factors you have on the GPU side, but it does on the CPU, so maybe that's a way to cut the CPU portion of the sieve.
5) Message boards : Generalized Fermat Prime Search : First *megaprime* in GFN16 (or GFN15) series (Message 127458)
Posted 55 days ago by Profile Rafael
Good news everyone. I found that hacked version of our manual sieving GPU app can work with huge b values. But it does something strange. It could only find factors above 1,8P. I did a minimal range of 1P-2P and it produced nothing first. I thought that my assumptions for this hack were wrong and moved to other things. But the app kept running. Later I've occasionally switched to this window and suddenly seen factors...

To be exact, the minimum factor it found was

1814652271329281 | 1814570323409552^65536+1

All factors are correct, I'm checking them. I don't know what's behind this and why it's not working at lower ranges. Although I've ported this app, most of math stuff in it is a black magic to me. I even cannot be sure that it's not missing some factors, there is no way to verify. Anyway, this will allow us to sieve much deeper and remove many thousands candidates.

The bad new is that it's still an open question how to sieve up to 1,8P; it's too slow on CPU but there are lot of candidates waiting to be removed from this range.

Jim said small sieving had to be done with specialized software back when we restarted 15/16 sieve to accomodate for the new OCL app, so I'm pretty sure that behaviour is expected, though I have no clue as to why.
6) Message boards : Sieving : Multiple GPU systems (Message 126852)
Posted 66 days ago by Profile Rafael
On a multi GPU system, can I restrict Sieving to one GPU and let BOINC have the other?

Yes. The sieve app runs on a single GPU at a time, and you can tell which one to use. Meanwhile in BOINC, you can tell it to ignore a given device so that it won't use it.

On a multi GPU system, does Sieving 'automatically' use both GPUs?

See above. If you want to run on more than one GPU at a time, you'll have to launch the app individually for each of them.

On a multi GPU system where one GPU is much better than the other, does Sieving care?

The app doesn't care for how good a GPU you use, so long as it supports the necessary features. Whether it's worth to sieve or use the card for something else, that's up to the user to decide.

But generally speaking, I find that Nvidia GPUs are better at sieving and AMD's are better at crunching.
7) Message boards : Number crunching : Is it better to have "C States" enabled or disabled in the BIOS? (Message 126771)
Posted 68 days ago by Profile Rafael
Wondering for max crunching obviously :)

If you're crunching, it doesn't matter. C states only proc when the processor is idling, so it won't make a difference whether they're enabled or not.

So leave it on and forget about it.
8) Message boards : Sieving : New automated manual sieving system (Message 126724)
Posted 69 days ago by Profile Rafael
my GPU cannot use the Open CL executable, so i downloaded the CUDA one with the dll, but somehow can't run it.
Can anybody help me?

What was your GPU again?
9) Message boards : AP26 - AP27 Search : New feature with latest AP27 gpu application (Message 126530)
Posted 73 days ago by Profile Rafael
Would systems with an Intel integrated GPU (ex HD 530) also experience screen lag or is the integrated GPU sufficient to look after occasional browsing needs etc?

Great work with the app.

Regardless of lag, it's not worth it to use the iGPU. If you have a decent chip, then you're pretty much guaranteed to also have a good CPU, at which point you're better off using the limited ram bandwidth to LLR rather than having it be stolen by a very weak GPU.
10) Message boards : General discussion : A new Mersenne prime was found (50th known) (Message 126312)
Posted 76 days ago by Profile Rafael
If GFN 23 aka "lucky" take only 23-24 hours on todays gf cards generation like 2080Ti..remind me relative short..
just if i compare to older times when was new nvidia 5xx or 6xx generations. take days to finnish one task..
maybe is time for bigger app .. i have no problem 7 day long task days on 2080Ti)). of course there is other factors what can complicated this big app ,,
For users wiht V100 nvidia is it just ..piece of cake..)
Problem is bigger app cannot by more lucky on prime.. but if try this many users.. i dont know.. i am not math spec..

Except there's no reason to, at least not just yet. If you can test GFN 23, you can test it's 22 equivalent, which will run faster by nature, so you're better off exausting the 22 range (either by checking everything or having GIMPS find something too large) before moving to 23.

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