For some time SIA was very profitable to mine but there was no public pool existing and difficulty became very high. I believe it's because of the FPGA farms that can use Wolf's implementation. Idea was to have in parallel some mining that will cover the electricity costs and check the luck with SIA's high variance. I did mining of SIA before and I know that down clocking the memory doesn't change the hash rate but lowers the power spent, meaning that it is very relaxed on GPU memory and can be mined in parallel with ETH. Last week price peak of SIA and calculation of 3 times more profit than ETH was a signal to start. Three rigs used, first with one 280X and 7870, second with 4 280X and last one with 3 280X and one 290. Win, Claymore dual miner in mode 1, siad 0.6.0 and precompiled sia_gpu_miner. With sia miner intensity up to 27 there were very low sia hash rates (280X in range of 50Mh/s) but almost no change in ETH hash rate. Intensity 28 dropped ETH hash rate at 35% of normal level and gave 510+ Mh/s on 280X and 600+ Mh/s on 290. More than 3 days passed and I didn't solved a SIA block, SIA profitability went down close to ETH, difficulty continue to rise, ambient summer temperatures gone higher,... so I gave up.
If someone wants to try and/or believe more in SIA than ETH can share dual mining experience. Or maybe Claymore can make ETH-SIA dual miner where SIA intensity could be fine tuned.
Here are some screenshots during and after unsuccessful try...
First one before...
...and afterward, more cool and relaxed.
Second one...
And third...
