[gmx-users] GPU ECC question

[Albert]

Hello:

  Recently I found a strange question about Gromacs-4.6.2 on GPU 
workstaion. In my GTX690 machine, when I run md production I found that 
the ECC is on. However, in my another GTX590 machine, I found the ECC 
was off:

4 GPUs detected:
   #0: NVIDIA GeForce GTX 590, compute cap.: 2.0, ECC:  no, stat: compatible
   #1: NVIDIA GeForce GTX 590, compute cap.: 2.0, ECC:  no, stat: compatible
   #2: NVIDIA GeForce GTX 590, compute cap.: 2.0, ECC:  no, stat: compatible
   #3: NVIDIA GeForce GTX 590, compute cap.: 2.0, ECC:  no, stat: compatible

moreover, there is only two GTX590 in the machine, I don't know why 
Gromacs claimed 4 GPU detected. However, in my another Linux machine 
which also have two GTX590, Gromacs-4.6.2 only find 2 GPU, and ECC is 
still off.

I am just wondering:

(1) why in GTX690 the ECC can be on while it is off in my GTX590? I 
compiled Gromacs with the same options and the same version of intel 
compiler

(2) why in machines both of physically installed two GTX590 cards, one 
of them was detected with 4 GPU while the other was claimed contains two 
GPU?

thank you very much

best
Albert