Hi all,

I am running Seti with Lunatics app on 2 iMac's (late 2012) that are both currently using windows 7 x64 via boot camp.

They are identical with the exception of 1 has a 3.2Ghz i5 and the other a 3.4Ghz i7. Both have 16GB of RAM and a GTX 680MX GPU but when I am running the Cuda tasks I have noticed the i5 machine can complete a task in ~2min 40s whereas the i7 machine is taking ~6min 30s.

Anybody any ideas on this? The computing preferences are also identical. The i5 has 4 cores no HT whereas the i7 has 4 cores with HT, not sure if this will affect it, but being GPU tasks I didn't think this would make any difference.

Thanks,

Dan

First test I would do is turn off HT on the i7 and see if it makes any difference.

Doubt many of us have been to that kind of boot camp:-)

Are the GPU's identical?

I'm assuming you are testing on the same W/U.

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You're only got two hosts on your Account, One running Windows 7 Professional x64, the other running Darwin 12.2.1, so i can't compare GPU tasks from one host to the other:

Computers belonging to Dan Stoneham

Not all MB tasks are of the same length, how long they take depends on the Angle Range,

Very High Angle Range tasks where the telescope is being swept across the sky take the shortest time to complete, about 2 minutes on my GTX460,
Normal AR (~ 0.44 AR) tasks where the telescope is static, but the earth rotates, take about 8 minutes on my GTX460,
Very Low Angle Range tasks where the telescope is pointed at a fixed point in space, take something like an hour or two to do, because of this they aren't sent to GPUs,
you can also get tasks that have an AR of 0.37 that take an extra minutes or two, and tasks outside the defination of VLAR that take extra time too,

Claggy

Thanks for your replies,

Newbie mistake, I thought each W/U was the same size, I hadn't realised there were different types :)

The GPU's are identical (GTX 680MX)

The 2 iMacs are on 2 different accounts but part of the same team. The 2 you see on my account (1 Windows, 1 Darwin) are actually the same machine just booted into different OS's.

Thanks,

Dan

You can keep HT enabled on i7 and limit the CPU to use 50% of processors. This way you have maximum number of CPU-FP units utilized and those extra HT cycles (cores) are reserved for GPU tasks requiring CPU for memory transfer/logic.

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To overcome Heisenbergs:
"You can't always get what you want / but if you try sometimes you just might find / you get what you need." -- Rolling Stones