GPU LL Questions

[axn]

Originally Posted by Primeinator

Pardon my ignorance... but why is this better if 1/24 is smaller than 1/8. Wouldn't a "1/8" speed reduction in the 590 be worse than the "1/24" reduction?

DP speed is reduced to 1/8th of SP. Not "speed is reduced by 1/8th of ..."

[Primeinator]

Originally Posted by axn

DP speed is reduced to 1/8th of SP. Not "speed is reduced by 1/8th of ..."

Ah. The mystery is solved! Thank you.

[Manpowre]

with the 1/8 on the 580/590 chip and the reduced number of cuda cores, it still performe great compared to 6xx fermi chip and 7xx kepler chips with a huge number of cuda cores but 1/24 dp speed of sp.

Just got 2x 590 boards here today, fired up one in the machine that had a 6970 board doing TFing.. and 58m exponents are going to be done in 4.5 days and the card does 2 of these simultaniously.. one Titan card does 2 58m exponents in 6 days.

great bang for the bucks.

[kladner]

Originally Posted by Manpowre

[SNIP].....great bang for the bucks.

And in the winter, great space heaters! Good thing your electricity is cheap.

[Manpowre]

Originally Posted by kladner

And in the winter, great space heaters! Good thing your electricity is cheap.

yeah,.. I have to move the machines out of the small office unfortunately.. into living room at some point. still 14 degrees C during night so for now ok, but once it goes to 5-9 degrees C, then they will heat up pretty good..

[Manpowre]

Originally Posted by Primeinator

Pardon my ignorance... but why is this better if 1/24 is smaller than 1/8. Wouldn't a "1/8" speed reduction in the 590 be worse than the "1/24" reduction?

No, 1/24 = 24 times slower when doing double precision which is exactly what cudalucas is doing to calculate.
1/8 = 8 times slower.. but 580/590 cards have fewer cudacores, but double precision is not so slow on that architecture.

Still 680/690 cards have 1/24 speed recuction with more cudacores they compete with 580/590 with fewer, but you can now purchase used 580/590 cards for less than $250.. which is great..

620 card has 1/24 speed reduction with fewer cudacores than 680, so naturally its going to be very slow..

Therefore 620 card should be used for single precision integers which is what MfaktC does.

[Manpowre]

Im running 62m-63m exponents on the 590 card now, and it takes 125 hours.
Since this is a multi gpu card, I can run 2 instances.. so in reality, I get 2 exponents done in 125h.

One titan card does the same exponent in about 85 hours. which makes the 590 card a winner, as titan can do 2 exponents in 170h.

[LaurV]

There is nothing new in what you say.

[Primeinator]

Do 590s consume a lot of electricity compared to a semi upper end i7

[kracker]

590=365W
4770K=84W

[Manpowre]

Originally Posted by kracker

590=365W
4770K=84W

please correct me, but the 590 doesnt use 365w with cuda. as there is overhead here. there is memcopy back to memory after the FFT operation, then there is memcopy to card again, then normalization etc.. so that doesnt put the card at 365w. more like 190w-200w.