20200525, 22:04  #12  
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
11001_{8} Posts 
Quote:
https://www.techpowerup.com/gpuspecs/radeon540.c3419 gives some idea of gpu specs. Slower than a GTX480, and much less power draw. 

20200526, 02:54  #13 
Feb 2005
Colorado
1000001110_{2} Posts 
I don't know if this is interesting to you guys or not, but I have occasionally been able to get Skylake CPUs on colab on an unpaid account. I'm pretty sure it supports AVX512.

20200526, 18:49  #14  
∂^{2}ω=0
Sep 2002
República de California
9,791 Posts 
Quote:
In retrospect, realizing that I have a need for an AVX512 build system now that the GIMPS KNL is gone, I should've considered getting a lowend SkylakeX cpu/mobo for my new multiGPU build. Haven't tried to cost things out in detail, but I suspect the $275 (incl. tax) I paid for the NUC could've instead paid for an upgrade of my bargain dualcore Celeron cpu/mobo ($120) to a SkylakeX quad  perhaps someone can tell me if $400 can get one such a quad cpu/mobo bundle. But, water under the bridge. And it'll be really interesting to headtohead compare the throughput and wattage of the new NUC to my old (and still crunching steadily away) AVX2 NUC which Mike/Xyzzy built for me way back when. BTW, I linked to the system I found because the seller apparently has multiple ones for sale, in case anyone else wants one. Last fiddled with by ewmayer on 20200527 at 19:30 

20200526, 19:20  #15  
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
11·419 Posts 
Quote:
Those who don't have the time or inclination to hit the cpu or gpu roulette jackpot and need reliable access of long duration go shopping. 

20200526, 23:25  #16  
Feb 2016
UK
605_{8} Posts 
Quote:


20200527, 11:56  #17 
"Mike"
Aug 2002
5·23·67 Posts 

20200527, 14:06  #18 
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
11·419 Posts 
KNL as a whole is gone in a sense;
"Intel announced they were discontinuing Knights Landing in summer 2018." https://en.wikipedia.org/wiki/Xeon_Phi#Knights_Landing 
20200527, 19:10  #19  
∂^{2}ω=0
Sep 2002
República de California
9,791 Posts 
Quote:
David Stanfill, who kindly volunteered to physically host the GIMPS crowdfunded KNL, went AWOL last year, and my multiple attempts to reach him via various routes proved futile. Thankfully, Ryan Propper offered to step in and resume the pair of F30 Pepin tests I had running on DS' gear (one @64M FFT on the KNL using an AVX512 build of Mlucas, one @60M FFT on a 32core Xeon server he had using an AVX2 build. Feel free to try to locate David, anyone  the KNL belongs to GIMPS, it would be nice to have it available for the purpose for which GIMPS members bought it. Last fiddled with by ewmayer on 20200527 at 19:11 

20200528, 09:38  #20 
Jan 2008
France
1020_{8} Posts 

20200531, 16:56  #21  
"TF79LL86GIMPS96gpu17"
Mar 2017
US midwest
11×419 Posts 
i38121U and RX540 performance on Win 10 in my NUC
Quote:
An extensive prime95 benchmarking tabulation of the i38121u is posted as an attachment of https://www.mersenneforum.org/showpo...19&postcount=5 I'd be very interested in comments from George or Ernst on the variations in the later plots, especially pages 5 and 6 as currently formatted. All the preceding was obtained with stock configuration (no overclocking, voltage adjustments, etc.) Last fiddled with by kriesel on 20200531 at 17:17 

20200531, 19:50  #22  
∂^{2}ω=0
Sep 2002
República de California
9,791 Posts 
Quote:
1. System powered up but otherwise idle; 2. Prime95 running in maxthroughput configuration; 3. Both Prime95 and gpuowl running in maxthroughput configuration. Re. heat, did you try popping the plastic top panel like I suggested? My i3NUC has yet to arrive, but if the chassis is similarly designed as my Broadwell NUC, there's a flat sheetmetal panel underneath the plastic cap which can serve as a radiator, and is also a tempting target for affixing a heatsinkpossiblewithfan. Quote:
The Bits/word plot on page 6, are the '+' data points just reflecting the internal bits/word thresholds of the program, and you found a logbased formula which gives a nice fit to those? That could be useful. Again by way of an alternate fit, I'd be interested in seeing how the data compare to the formula I use in Mlucas, in the codebox below, with Wbits being the output you want. Note that AsympConst is a tunable parameter which moves the entire resulting curve up (allowing larger p at each N) or down ... if e.g. my 0.6 setting gives a curve whose shape matches your data points but which is a bit below them, try 0.7, 0.8, etc. In regression form we'd be wanting the regression to tell us the bestbit value of said parameter. Code:
uint64 given_N_get_maxP(uint32 N) { const double Bmant = 53; const double AsympConst = 0.6; const double ln2inv = 1.0/log(2.0); double ln_N, lnln_N, l2_N, lnl2_N, l2l2_N, lnlnln_N, l2lnln_N; double Wbits, maxExp2; ln_N = log(1.0*N); lnln_N = log(ln_N); l2_N = ln2inv*ln_N; lnl2_N = log(l2_N); l2l2_N = ln2inv*lnl2_N; lnlnln_N = log(lnln_N); l2lnln_N = ln2inv*lnlnln_N; Wbits = 0.5*( Bmant  AsympConst  0.5*(l2_N + l2l2_N)  1.5*(l2lnln_N) ); maxExp2 = Wbits*N; /* fprintf(stderr,"N = %8u K maxP = %10u\n", N>>10, (uint32)maxExp2); */ return (uint64)maxExp2; } Last fiddled with by ewmayer on 20200531 at 19:51 

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