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Old 2003-09-29, 22:15   #1
PageFault
 
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Default Request: P-1 79M

I have a 79M LL test but no machine with enough ram to do P-1. Added problem is that it is beyond SSE2 limits, i.e., has to be done on a AMD.

I don't know what you guys are doing here, but if anyone has over a GB of prime95 allocated ram we could arrange something - do my P-1 test and in the meantime I'll do a block of yours on my 2 GHz tbred with 512 MB.

My test would have to be done offline as I am a TPR member and our exponents cannot be unreserved - you would have to send me the .spl file for the result to be accepted.

Any ideas ? Last thing I want to do is a year of LL on a test with a findable factor.
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Old 2003-09-29, 23:17   #2
GP2
 
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Default Re: Request: P-1 79M

Quote:
Originally posted by PageFault
I have a 79M LL test but no machine with enough ram to do P-1. Added problem is that it is beyond SSE2 limits, i.e., has to be done on a AMD.
Perhaps it could be done on a P4 if you set
CpuSupportsSSE2=0
in local.ini? (and remember to delete it again when it finishes). That's from undoc.txt.

Sorry, I have under 1 GB myself.

Last fiddled with by GP2 on 2003-09-29 at 23:17
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Old 2003-09-29, 23:27   #3
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How much would that slow it down?

I've been trying to figure a way to get this particular exponent P-1 factored for a long time...
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Old 2003-09-30, 01:06   #4
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I recall the pre SSE2 client was something like three times slower than the first SSE2 release. So, dog slow is the word, akin to a 1 GHz tbird or so. Added complication is that the client treats cpu's differently - on AMD's I noticed that, for a block of exponents of similar size, the client cut back on the bounds compared to northwood, using same ram. Doubling the ram (256 to 512) resulted in the same bounds for AMD and Intel (256 MB). I don't know if cpu speed had anything to do with it but it appears that a fully loaded AMD, i.e., 2 GB ram, would do the same depth as a Northwood with 1 GB, this most likely being satisfactory.
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Old 2003-09-30, 06:08   #5
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Prime95 tells me it might take around two weeks... That's a long time...
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Old 2003-10-01, 00:50   #6
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I started it for comparison:

B1=770000
B2=11742500
Prob. of finding factor = 4.54%

I started it with the normal test line, so status doesn't show how much time for P-1. First iteration, 479.486 sec. for 0.09% of stage 1 ... at that rate, more than six days to do the easy part ...

Looks like I'm going to have to hold off on doing that test, or I'm going to have to hail to the
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Old 2003-10-01, 19:32   #7
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Default Re: Request: P-1 79M

Quote:
Originally posted by PageFault
I Added problem is that it is beyond SSE2 limits, i.e., has to be done on a AMD.
I did not know there was such a limit. That means exps above a certain value canĀ“t be tested on P4s, at least taking advantage of what makes them fast?
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Old 2003-10-01, 23:13   #8
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By the time we get to the 70M range, George will have fixed that...
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Old 2003-11-22, 21:32   #9
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I have a DL380/G2 with 2gigs of ram (it's a dual P3/1.15 something). I think my boss will let me play with it until january sometime, so I'd be willing to run the P-1 for you....

Let me know, else I'll continue to do some other Mersenne-ary work.
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Old 2003-11-22, 22:16   #10
pakaran
 
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Quote:
Originally posted by Xyzzy
How much would that slow it down?

I've been trying to figure a way to get this particular exponent P-1 factored for a long time...
It would slow it down by a factor of 3 to 3.5, probably more.

Memory for XPs is in the multiple hundreds of dollars for that size range. Otherwise I'd get some and do it for you.
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Old 2003-11-22, 22:17   #11
pakaran
 
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Quote:
Originally posted by Xyzzy
By the time we get to the 70M range, George will have fixed that...
I'd hope so. I think that should be 5 years at least.
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