[quote=TheJudger;223979] gives most bank for the buck [/quote]

Point of Anglo-American: the expression is
"bang for buck". Interpret the literal meaning as you like:smile:

David

[quote=davieddy;223987]Point of Anglo-American: the expression is
"bang for buck". Interpret the literal meaning as you like:smile:

David[/quote]From [url]http://www.randomhouse.com/wotd/index.pperl?date=19971219[/url] :

[quote]The phrase, which means 'value for one's money', was originally a political one. Its first use was quite literal: With [B]bang[/B] referring to 'firepower' or 'weaponry', it really did mean 'bombs for one's money'. The alliteration of [B]bang[/B] and [B]buck[/B] helps to make the phrase memorable.

The earliest confirmed mention of [B]bang for the buck[/B] is found in 1968 in the first edition of William Safire's [B]New Language of Politics[/B]. Mr. Safire claims that the phrase was coined in 1954 by Charles E. Wilson, the Secretary of Defense, in reference to the "massive retaliation" policy of John Foster Dulles.

While [B]bang[/B] has been used in sexual senses since the seventeenth century, it is unrelated to our phrase.[/quote]

Hi David, hi cheesehead,

just a stupid typo... :sad:

Since 460GTX are cheaper now they give the most ban[B]g[/B] for the buck in mfaktc. 768MiB variants are OK, mfaktc doesn't need much memory/memory bandwidth on GPU.

Anyway, here are the performance measurements of a stock GTX 480:
[CODE]
kernel | M66362159, 2^64 to 2^67 | M3321932839, 2^50 to 2^71
-------+-------------------------+--------------------------
71bit | 127.0M/s | 98.7M/s mfaktc-0.10
75bit | 227.4M/s 179.1% | 177.8M/s 180.1%
95bit | 192.2M/s 151.3% | 149.8M/s 151.8%
[/CODE]

Oliver

I thought I'd give this another try. I'm using a 2.4GHz Core 2 Quad processor with a GTX 480 card. Keeping the GPU busy requires 3 instances of mfaktc. Otherwise, SievePrimes just drops to 5000. Each instance is running at about 58.4 M/s on a >100M digit number, so a total of about 175M/s. This seems consistent with your chart above. This corresponds to taking three >100 digit candidates to 78-bits in 4 days or 79-bits in 8 days.

Hi frmky,

yep, GTX 480 is a beast. :smile:
Did you try to enable MORE_CLASSES in params.h? This lets the sieve running more efficient at the cost of more initializations. So this is usefull for "long runs" where each class takes > 60 seconds without MORE_CLASSES enabled. For a 100M digit to 2^79 it is a clear advantage to enable it.

Hint: currently mfaktc 0.11 is out to some people here in the forum for testing. If everything is right I'll release 0.11 within one week. :smile:
You'll like mfaktc 0.11 because the sieve is ~20% faster (measured on i7), but I think you'll still need 3 instances on your machine to keep your GTX 480 busy.
Note: a ~20% faster sieve [B]doesn't[/B] mean a 20% improvement on overall performance in general!


Oliver

Why there is no Win' 32bit port's? Somebody can make it port for last version?

[SIZE="1"]Sorry for my English :redface:[/SIZE]

Hi Lorenzo,

hopefully no port is needed, we need just a win32 build! :smile:
64bit is prefered but not necessary simply because they are faster (my sieve runs faster on 64bit).
Actually I can't generate Windows binaries, sorry!
But perhaps someone here in the forum can generate them.

Oliver

[QUOTE=TheJudger;227313]Hi Lorenzo,

hopefully no port is needed, we need just a win32 build! :smile:
64bit is prefered but not necessary simply because they are faster (my sieve runs faster on 64bit).
Actually I can't generate Windows binaries, sorry!
But perhaps someone here in the forum can generate them.

Oliver[/QUOTE]

Hi Oliver,

I'm trying to install 64-bit system:
1. Windows XP Professional x64 Edition
2. nVidia Forceware v258.96 International (WinXP x64) WHQL
3. CUDA ToolKit 3.1 (Win64)
4. Video Card nVidia Geforce 8500 GT (256 Mb DDR2)
5. mfaktc-0.09-win64-eoc

But when i run mfaktc-0.09-win64-eoc:
[CODE]mfaktc v0.09-Win

Compiletime Options
THREADS_PER_GRID 983040
THREADS_PER_BLOCK 256
SIEVE_SIZE_LIMIT 32kiB
SIEVE_SIZE 230945bits
VERBOSE_TIMING disabled
MORE_CLASSES disabled

Runtime Options
WARNING: Cannot read SievePrimes from mfaktc.ini, using default value (25000)
SievePrimes 25000
WARNING: Cannot read SievePrimesAdjust from mfaktc.ini, using default value (0)
SievePrimesAdjust 0
WARNING: Cannot read NumStreams from mfaktc.ini, using default value (3)
NumStreams 3
WARNING: can't read WorkFile from mfaktc.ini, using default (worktodo.ini)
WorkFile worktodo.ini
WARNING: Cannot read Checkpoints from mfaktc.ini, enabled by default
Checkpoints enabled

CUDA device info
name: GeForce 8500 GT
compute capabilities: 1.1
maximum threads per block: 512
number of multiprocessors: 2 (16 shader cores)
clock rate: 1400MHz

[B]cudaStreamCreate() failed[/B][/CODE]
What i doing wrong?

Hi Lorenzo,

first of all I recommend that you download the source tarball of mfaktc 0.09.
[url]http://www.mersenneforum.org/showpost.php?p=220929&postcount=295[/url]
Download and put the mfaktc.ini into the directory of your mfaktc executable.
This will remove the warnings and gives you some more control over mfaktc.

But I think this won't solve you issue. You could try to set NumStreams to 1 on mfaktc.ini than.

Aillas reported the same(?) issue on Linux with his Nvidia quadro 140M. On his system mfaktc 0.10 works.
I've no clue what happens there, the code which does stream creation is virtually untouched between those two versions, the difference is that mfaktc 0.10 prints the stream number when the stream creation failed.

Oliver

P.S. is this an overclocked GPU? According the wikipedia it should run at 900MHz.

[QUOTE=TheJudger;227747]
Aillas reported the same(?) issue on Linux with his Nvidia quadro 140M. On his system mfaktc 0.10 works.
I've no clue what happens there, the code which does stream creation is virtually untouched between those two versions, the difference is that mfaktc 0.10 prints the stream number when the stream creation failed.
[/QUOTE]

Hi,

bad news. I can't make it run since one week. In a bunch of Linux update, I also update to the latest nvidia driver. BIG MISTAKE. The computer was unusable.
I remove all nvidia driver and re install manually the 254.35 (I think), but now, mfakt 0.10 doesn't work anymore.

If you want, I can try your 0.11 version;
I think I will upgrade my linux to a 64 bit version too.

Hi Aillas,

mfaktc 0.11 won't fix this, again the stream creation code is unchanged to the previous version. And don't spent time for searching version 0.11, it is not released yet. This should happen in the next few days.

Sorry for asking again: Can you try the nvidia SDK code samples? [url]http://developer.nvidia.com/object/cuda_download.html[/url]

Oliver