GTX 780 TI

[kracker]

@LaurV: I agree 100%. If the 780 ti has the DP switch, then definitely yes. Maybe it does have the speed that James's site has, but this leads me to either of these two:

• Titan benchmarks are not with the "DP" switch on.
• The 780 Ti was based on the Titan

Hmm... looking here maybe the 1000 MHz boost in memory? But still, something is not right. It is clear though, the Titan has 1/3 FP64, the 780 ti 1/24.

Again, I don't know... Just speculation.
-AMD guy


@TheMawn: You made yourself perfectly clear. Please take a good look at the Titan, 780 and 780 Ti's specs and you'll come to a different conclusion.

EDIT: http://images.anandtech.com/graphs/graph7492/59703.png

[LaurV]

Originally Posted by kracker

maybe the 1000 MHz boost in memory?

I considered the memory boost, and the additional cuda cores, that is why I said "six times" and not "eight times" faster for DP, see my post. Because otherwise, 1/3 is 8 times faster than 1/24, for the same clock and the same number of cuda cores.

Now, if you are talking about "DP switch", that would be a totally different thing, and it would explain a lot of things... If the 780Ti has a "DP switch", to raise the DP clock to "normal" (instead of 1/8 as it is now) to make it work "full speed", than both boards would do same SPDP ratio (1/3), and you would get about 5-10% from the clock ratios, about 8-12% from the additional cuda cores, THAT would perfectly justify the 13-17% more speed for the 780Ti.


So, does the 780Ti has a DP switch? Maybe that is all it is about?

[axn]

Originally Posted by LaurV

Now, if you are talking about "DP switch", that would be a totally different thing, and it would explain a lot of things... If the 780Ti has a "DP switch", to raise the DP clock to "normal" (instead of 1/8 as it is now) to make it work "full speed", than both boards would do same SPDP ratio (1/3), and you would get about 5-10% from the clock ratios, about 8-12% from the additional cuda cores, THAT would perfectly justify the 13-17% more speed for the 780Ti.


So, does the 780Ti has a DP switch? Maybe that is all it is about?

Then NVIDIA would be stupid to sell it for $700 (vs $1000 for Titan). More probable is Titan benchmarks were obtained with the DP switch off. If only I had a Titan to test out my theory

[kracker]

Originally Posted by LaurV

I considered the memory boost, and the additional cuda cores, that is why I said "six times" and not "eight times" faster for DP, see my post. Because otherwise, 1/3 is 8 times faster than 1/24, for the same clock and the same number of cuda cores.

Now, if you are talking about "DP switch", that would be a totally different thing, and it would explain a lot of things... If the 780Ti has a "DP switch", to raise the DP clock to "normal" (instead of 1/8 as it is now) to make it work "full speed", than both boards would do same SPDP ratio (1/3), and you would get about 5-10% from the clock ratios, about 8-12% from the additional cuda cores, THAT would perfectly justify the 13-17% more speed for the 780Ti.


So, does the 780Ti has a DP switch? Maybe that is all it is about?

Sorry, my brain was foggy...

One thing I know, the 780 TI does NOT have the DP switch.

[LaurV]

Originally Posted by kracker

One thing I know, the 780 TI does NOT have the DP switch.

Then it must be what axn said: the benchmark for Titan was done with the DP switch disabled. This raises another question: how fast is a Titan with the switch enabled? 300 GHzDays/Day of front-LL?? 400? 500? (for comparison: the 580's value in the table is ~30, but it can do 35, max 40, when overclocked and well cooled; for Titan, the value in the table is ~60, which multiplied by 8, assuming the theory is right, and thinking also about memory limitation, but assuming you can cool it properly to avoid thermal throttling, which for sure I can do...)

Mother of the gun! Aren't your fingers twitching? I would sacrifice the additional $300 for a Titan over the price of a 780Ti, only to test this theory... Only if it wouldn't be so freaking difficult to get those Titans in Thai. I will visit some shops this weekend to see what they offer, and if they not, I may plan a trip to HK or S-pores soon.... I may change all my park of 580's to Titans.... dreaming.... twitching... twitching... dreaming...

BTW, what is Santa Claus doing this year? Does anyone know?

[kladner]

Originally Posted by LaurV

.....

BTW, what is Santa Claus doing this year? Does anyone know?

Santa LaurV could dispose of those cast-off 580's over by here.

[ET_]

A nice article running GPU benchmarks on Linux and Windows:

Here.

Luigi

[Manpowre]

Well, this is what I get from each of my 2x titans and DP switch on.
73m exponents, 68hours - 206ghz days

= 72.79 ghz days per titan.

There is overhead in the GPU cards which actually slows down the titan, and that is the memcopy back and forth.

73m exponents:
- Titan - 2.9-3.0 ms per iteration
- 580 - 6.6-6.8 ms per iteration
- 590 - 8.2-8.4 ms per iteration (you get 2 simultaniously on one board though)

Also,

I have done FFT benchmark to choose the fastest FFT length for each platform within the error criteria of 0.25. The cudalucas FFT length for the 73m exponents are 43xx something, while I found it alot quicker with 4096 on the titans. The 580/590 uses the 43xx FFT length that cudalucas picks.

So there are many things that make the benchmark not look so good.

[axn]

Originally Posted by Manpowre

= 72.79 ghz days per titan.

which is higher than the 68.1 reported for 780 Ti (and 60.7 reported for Titan itself).

Although, the 780 Ti still wins out when you factor in the cost.

[kracker]

I stand on my original belief. The 780 Ti does not perform as well as in the charts.

[Manpowre]

honestly, I believe the 780 TI will perform something like 4-4.5ms for the 73m exponents with 4096k FFT length.

It is not only about the 1/3 DP speed of SP, or 1/24. it is also that cudalucas is made in such a way where there is memcopy between host memory and GPU card 2 times for each iteration. This takes alot of time too. With a better memory bus for the 780TI, I believe it will perform good, or similar like the 290x, which I also expect to be at 4-4.5m for 4096 FFT length.

This means something like 40-45 ghz days with LL test. I dont believe in 55-60ghz days for 780ti.

also, if you need 2x 780ti's to compute like almost like one titan, you also loose one slot on host machine. but if you only are going to have 1x machine and can afford 2x 780s for gaming, then 2 of these are good.

I am looking for good titan deals right now.

I also saw rumors that nvidia will make a dual gpu card 790 and titan ultra/black edition with 1/3 DP and 2880 cudacores. this means titan1 prices will drop soon. probably to the level of 780ti.

I do think the charts for 780ti and titan has to be updated.!