[QUOTE=kracker;325861]Sure! Although my firepower sucks, Count me in :smile:[/QUOTE]

OK, thanks guys.

I have started bringing in candidates. Only a thousand at a time until we've got a comfortable margin.

Go to the [URL="https://www.gpu72.com/account/getassignments/dctf/"]DC TF Assignment form[/URL], set the "Will factor to" field to be 70, and the "Option" to be "Lowest Exponent".

I would suggest that people try to only take a hundred or so at a time, and try to return results at least every hour or so, at least at the start of this exercise.

[QUOTE=chalsall;325868]OK, thanks guys.

I have started bringing in candidates. Only a thousand at a time until we've got a comfortable margin.

Go to the [URL="https://www.gpu72.com/account/getassignments/dctf/"]DC TF Assignment form[/URL], set the "Will factor to" field to be 70, and the "Option" to be "Lowest Exponent".

I would suggest that people try to only take a hundred or so at a time, and try to return results at least every hour or so, at least at the start of this exercise.[/QUOTE]

Thanks :smile:

[QUOTE=chalsall;325868]OK, thanks guys.

I have started bringing in candidates. Only a thousand at a time until we've got a comfortable margin.

Go to the [URL="https://www.gpu72.com/account/getassignments/dctf/"]DC TF Assignment form[/URL], set the "Will factor to" field to be 70, and the "Option" to be "Lowest Exponent".

I would suggest that people try to only take a hundred or so at a time, and try to return results at least every hour or so, at least at the start of this exercise.[/QUOTE]

This work can be fetched via the GPU72WorkFetcher utility by setting the URL in the config file to
[B]URL:[url]https://www.gpu72.com/account/getassignments/dctf/[/url][/B]

(set the pledge and option as Chris has stated)

I will join with one gtx580, for a week or so, starting tonight (my time) to help setting this debate once forever :smile:

[QUOTE=LaurV;325906]I will join with one gtx580, for a week or so, starting tonight (my time) to help setting this debate once forever :smile:[/QUOTE]

Coolness. Thanks. :smile:

took 30 expo for 69-70.... just enough for the night (GTI 560 normal) around 26 minutes for a 31075xxx exponent (3.85GhzD)

[QUOTE=henryzz;325845]Adding to the confusion doesn't James' page still rely on data from mfaktc 1.19 not 1.20. Isn't the new version quite a bit more efficient as it allows the cpu to be used for DC/LL.[/QUOTE]My [url=http://www.mersenne.ca/cudalucas.php?model=13]GPU TF-LL comparison page[/url] is purely GPU crossover points, although you are correct that GPU-sieving does allow the CPU to be used for other tasks. But the performance numbers reflect mfaktc v0.20 performance (as does the [url=http://www.mersenne.ca/mfaktc.php]GPU-TF expected performance page[/url]).

[QUOTE=Prime95;325832]It would be great if James could change the chart to show the DC breakeven point when P-1 has been performed (the factoring chart LaurV pointed to, [url]http://www.gpu72.com/reports/factoring_cost/[/url], gives enough information to produce a fairly accurate adjustment to the chance of finding a factor). For extra credit, the web page could offer a checkbox to show the crossover points assuming no P-1 done.[/QUOTE]I'll see what I can come up with over the next few days.

[QUOTE=chalsall;325850]... but I'm going to run a few hundred TF runs immediately in front of the wave front in 31M to 70 so we can get a reasonable idea as to what type of percentage we might expect. (31M to 70 has only had 83 attempts before, with zero factors found, so we don't actually have any useful data on what we might expect exactly there.)[/QUOTE]

[url]http://www.mersenne.org/various/math.php[/url] says:
[QUOTE]the chance of finding a factor between 2[SUP]X[/SUP] and 2[SUP]X+1[/SUP] is about 1/x[/QUOTE]
So, assuming all exponents are already at 69 and being brought to 70, we should expect 1/69, or 1.45%, to have factors, right? Edit: I think I just realized why it's not that simple: P-1 factoring will find a portion of the factors. Since not every exponent was P-1'd to the same extent, this becomes much harder to calculate over the range, and to get an accurate figure without simply testing and looking at results, you'd have to get all complete P-1 bounds and calculate based on that.

[QUOTE=Mini-Geek;325958] Since not every exponent was P-1'd to the same extent, this becomes much harder to calculate over the range...[/QUOTE]

All true, but we aren't seeking perfection here. I'd say if we know our chance of finding a factor within 10%, that's good enough to determine a very reasonable DCTF crossover point.

Using chasall's 1.1546% number we get 1 chance in 86.6 of finding a factor. James knows how to turn that into crossover points.

Just started... it is doing one every 40 min, about ~200M/s on mfakto, 7770.

Took 100 last night; I'm doing one every 12 minutes.