For anyone interested here are the GPU-Z screenshots for my GTX 980 running mfaktc and then running CudaLucas.

[QUOTE=Mark Rose;392102]
Perhaps code changes could be made to reduce CUDALucas's FP64 usage.[/QUOTE]
Sorry, the LL test has got to have double precision if you're using floating point transforms. We (George and I) briefly considered using integer number-theoretic FFTs which would get the full throughput of the new GPUs, but I haven't seen a hardware configuration where that would be faster, in 15 years of trying. There's also the danger that in the time it takes to build GPU-optimized number-theoretic FFTs, the next model of GPU will be released which makes them unnecessary :)

[QUOTE=Roy_Sirl;392138]For anyone interested here are the GPU-Z screenshots for my GTX 980 running mfaktc and then running CudaLucas.[/QUOTE]

So it's a voltage limit that's capping the power consumption at 72% when running cudalucas. I don't run into that.

[QUOTE=Roy_Sirl;392138]For anyone interested here are the GPU-Z screenshots for my GTX 980 running mfaktc and then running CudaLucas.[/QUOTE]

That is very interesting. I do point out that the memory controller is running much harder for CuLu.

Hm.. What expo were you doing, which uses only 50% of the memory? Or is this normal for 980 cards?
My (unlocked) Titans maximize both the gpu and the memory when LL, when set to double precision.

[QUOTE=LaurV;392176]Hm.. What expo were you doing, which uses only 50% of the memory? Or is this normal for 980 cards?
My (unlocked) Titans maximize both the gpu and the memory when LL, when set to double precision.[/QUOTE]

Maxwells have large L2 cache (256KB vs 2MB) and much more crippled DP thruput.

780Ti CUDALucas GPU-Z, 69.5M, 4M FFT, 3.6 ms/iter

[QUOTE=stars10250;392229]780Ti CUDALucas GPU-Z, 69.5M, 4M FFT, 3.6 ms/iter[/QUOTE]
For this card, can you switch to DP? (i.e. do you have the option in nvidia control center/panel?)
I don't believe that the clock is for a DP-enabled card. For Titan, when I enable DP, the clock goes down from ~1200 to ~850.
Just curious, thanks in advance.

[QUOTE=LaurV;392246]For this card, can you switch to DP?[/QUOTE]

No. There is a CUDA setting but it's just for specifying which GPUs can be used by CUDA applications. Mine it set to use both video cards by default. I've read elsewhere that you do have to turn on dual precision with titan. It is disabled as it reduces performance in non DP applications.

[QUOTE=LaurV;392246] I don't believe that the clock is for a DP-enabled card.[/QUOTE]

It was running CUDALucas at the time of the screenshot and that makes extensive use of DP. I get the same clock numbers in MSI Afterburner overclock software, ASUS GPU tweak software, and in CPU-Z. I've seen the clock jump down when I unload it by turning off the CUDALucas calculation, but as soon as I launch the program it jumps back up to full speed.

[QUOTE=stars10250;392285]It was running CUDALucas at the time of the screenshot and that makes extensive use of DP. I get the same clock numbers in MSI Afterburner overclock software, ASUS GPU tweak software, and in CPU-Z.[B] I've seen the clock jump down when I unload it by turning off the CUDALucas calculation,[/B] but as soon as I launch the program it jumps back up to full speed.[/QUOTE]

This is power saving kicking in. The clocks go down, as well as the voltage.