mersenneforum.org  

Go Back   mersenneforum.org > Great Internet Mersenne Prime Search > Hardware > GPU Computing

Reply
 
Thread Tools
Old 2010-12-10, 23:17   #34
nucleon
 
nucleon's Avatar
 
Mar 2003
Melbourne

5·103 Posts
Default

Quote:
Originally Posted by CRGreathouse View Post
I'm seeing 181 watts for the i7 under load. So for your claim "Even when comparing power needed per primality test, they are less efficient than core i7's and other recent CPUs" to hold, the GTX 295 needs to be less than 2.7 times faster than the i7 -- or 10.8 times faster than a single (physical) core. Is that so?
My 460GTX does 3.7GHz-days per _hour_ of TF, or 88.8 GHz-days per day.

My core quad-core i7-930 (by my estimation) does 12GHz-days per day all cores utilized.

My GPU is at least 7times faster than my CPU running TF. Scaling the figures presented on the new gpu CUDA code a GTX480 looks like being 4times faster than my cpu on LL testing*.

I haven't checked power consumption fully populated.

-- Craig
*Take the 4times figure with a grain of salt. Large margin of error. Lots of assumptions and no way I can verify this figure for me personally.
nucleon is offline   Reply With Quote
Old 2010-12-11, 00:25   #35
ckdo
 
ckdo's Avatar
 
Dec 2007
Cleves, Germany

2·5·53 Posts
Default

Quote:
Originally Posted by nucleon View Post
My 460GTX does 3.7GHz-days per _hour_ of TF, or 88.8 GHz-days per day.
That's lowish. My MSI N460GTX HAWK does around 107 GHzd/d on a Q6600 while the CPU is running 4 LLs on exponents in the 41M range (bad idea, I know). All at stock speed, that is, and with X fully responsive. There's probably plenty of room for improvement on my end.
ckdo is offline   Reply With Quote
Old 2010-12-11, 04:27   #36
nucleon
 
nucleon's Avatar
 
Mar 2003
Melbourne

5·103 Posts
Default

I think it's the win7 gui. I have the full aero interface enabled.

As I move around to certain objects onscreen, I see the rate drop.

-- Craig
nucleon is offline   Reply With Quote
Old 2010-12-12, 10:52   #37
Brain
 
Brain's Avatar
 
Dec 2009
Peine, Germany

331 Posts
Default Back to hardware

Assumption 1: The GTX 460 has lost almost all advanced computing features / double precision support (compared with 470/480)!?
Fact 1: The GTX 470/480 have only 25% of their possible double precision throughput (ref here) to protect the Tesla cards.

I always thought DP support was mandatory (for LL)?

Please check my facts and give me a hint what kind of graphics hardware fits Mersenne's needs best. ;-)

I my opinion, we do not need more power on the TF part. I'd really love to see CUDA P-1.
Brain is offline   Reply With Quote
Old 2010-12-12, 21:34   #38
cheesehead
 
cheesehead's Avatar
 
"Richard B. Woods"
Aug 2002
Wisconsin USA

22·3·641 Posts
Default

Quote:
Originally Posted by Brain View Post
I always thought DP support was mandatory (for LL)?
Yes, number of guard bits required renders SP too inefficient.

Quote:
I'd really love to see CUDA P-1.
Yes!

But how much memory is available for stage 2? My sparse understanding about GPUs is that some have on-board RAM, while others (or all) use some of main RAM. Would transfer speeds in the latter case be a bottleneck?
cheesehead is offline   Reply With Quote
Old 2010-12-12, 22:07   #39
Mr. P-1
 
Mr. P-1's Avatar
 
Jun 2003

7×167 Posts
Default

Quote:
Originally Posted by cheesehead View Post
But how much memory is available for stage 2? My sparse understanding about GPUs is that some have on-board RAM, while others (or all) use some of main RAM. Would transfer speeds in the latter case be a bottleneck?
If that's a problem, then just do stage one on the GPU.
Mr. P-1 is offline   Reply With Quote
Old 2010-12-12, 22:57   #40
Mini-Geek
Account Deleted
 
Mini-Geek's Avatar
 
"Tim Sorbera"
Aug 2006
San Antonio, TX USA

10AC16 Posts
Default

Quote:
Originally Posted by cheesehead View Post
But how much memory is available for stage 2? My sparse understanding about GPUs is that some have on-board RAM, while others (or all) use some of main RAM. Would transfer speeds in the latter case be a bottleneck?
All GPUs that would likely be used for CUDA work (I'd be jumping to conclusions to say "all CUDA-capable GPUs" - but I think it's practically that) are parts of discrete graphics cards, (as opposed to integrated to the motherboard or CPU) which always include on-board RAM. E.g. a current good pick in the $200 range is a GTX 460 GPU on a card with 1 GB of RAM. I don't see any reason, in principle, why most of this memory can't be used for P-1 stage 2.

Last fiddled with by Mini-Geek on 2010-12-12 at 22:59
Mini-Geek is offline   Reply With Quote
Old 2010-12-13, 17:38   #41
Andrew Thall
 
Dec 2010

23 Posts
Default

@Brain: Fact #1 is true but irrelevant. LL needs the double precision only for the FFT squaring; as I mentioned before, I get better timings from the Tesla 2050 over the GTX 480 only if I overclock it to the same core-processor speed (1400 MHz); otherwise, the greater number of processors on the GTX more than makes up for the better double precision performance. Surprising, but FFTs have to move a lot of data, too; don't assume that they're time bound by the double-precision multiplies, particularly with the way smart compilers reorder operations to get maximum hardware utilization.

Last fiddled with by Andrew Thall on 2010-12-13 at 17:40
Andrew Thall is offline   Reply With Quote
Old 2010-12-13, 19:16   #42
KingKurly
 
KingKurly's Avatar
 
Sep 2010
Annapolis, MD, USA

33·7 Posts
Default

I take it that if I want to get in on this fun, I'll have to replace my ATI Radeon HD 5450 that came with my store-built PC? The AMD Phenom II X6 in it is doing great, but this GPU computation looks very promising and interesting. Obviously the ATI card is not going to do CUDA, that much I am aware of.

The machine is currently headless and primarily used for GIMPS. I guess I would be in the market for a new Nvidia card and perhaps a new power supply? (I'll have to look at what's in there, I haven't the faintest clue.)
KingKurly is offline   Reply With Quote
Old 2010-12-13, 20:43   #43
Brain
 
Brain's Avatar
 
Dec 2009
Peine, Germany

33110 Posts
Default GTX 560

Quote:
Originally Posted by KingKurly View Post
The machine is currently headless and primarily used for GIMPS. I guess I would be in the market for a new Nvidia card and perhaps a new power supply? (I'll have to look at what's in there, I haven't the faintest clue.)
I read first reviews on Nvidia's new GTX 5XX series. They seem to have done a very good job and a lot better than for GTX 4XX. But a 550W system power supply for a GTX 570 (ref) is too much for me. Latest rumors say its small brother GTX 560 will arrive in late January 2011. That one could become best choice (depending an CUDA cores / capabilities).

Quote:
Originally Posted by KingKurly View Post
I take it that if I want to get in on this fun, I'll have to replace my ATI Radeon HD 5450 that came with my store-built PC? The AMD Phenom II X6 in it is doing great, but this GPU computation looks very promising and interesting. Obviously the ATI card is not going to do CUDA, that much I am aware of.
I own an ATI 5770. --> No CUDA.
Brain is offline   Reply With Quote
Old 2010-12-29, 04:05   #44
ixfd64
Bemusing Prompter
 
ixfd64's Avatar
 
"Danny"
Dec 2002
California

2,411 Posts
Default

Hmm, it's been over two weeks since was any update. I hope this doesn't get swept under the rug.
ixfd64 is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
mfaktc: a CUDA program for Mersenne prefactoring TheJudger GPU Computing 3506 2021-09-18 00:04
Do normal adults give themselves an allowance? (...to fast or not to fast - there is no question!) jasong jasong 35 2016-12-11 00:57
Find Mersenne Primes twice as fast? Derived Number Theory Discussion Group 24 2016-09-08 11:45
TPSieve CUDA Testing Thread Ken_g6 Twin Prime Search 52 2011-01-16 16:09
Fast calculations modulo small mersenne primes like M61 Dresdenboy Programming 10 2004-02-29 17:27

All times are UTC. The time now is 14:14.


Wed Oct 20 14:14:02 UTC 2021 up 89 days, 8:43, 0 users, load averages: 1.20, 1.25, 1.12

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.