Maybe because AMD is only good at dagger hashimoto, cryptonight and a bit on equihash? Nvidia is extremely better at most algo's. I seen coins where a 1070 does x10 better than any rx card.

As Hangterisaan said, Nvidia cards perform much better on most algos. The 7950 is an old card, I think it can't keep up with todays demands. Does the miner show any hash rate data?

it shows around 2.5-3mh (people with 1050ti get 10) with i=20 but like i said i tried different "i" ...  got absolutely nothing accepted. not a single coin. (not a single share accepted/rejected)
just wasted some time and electricity.
without "i" speed drops to less than 200 kilohashes   anyway closed it.

You're probably getting constant hardware errors, I can't mine this coin either with r9 270x, there is something wrong with the miner

Yes it is, I also installed the lastest drivers and opencl for intel...
Listing OpenCL devices.
FORMAT: [deviceID] deviceName
[ 0 ] GeForce GTX 760
        CL_DEVICE_TYPE: GPU
        CL_DEVICE_GLOBAL_MEM_SIZE: 2147483648
        CL_DEVICE_MAX_MEM_ALLOC_SIZE: 536870912
        CL_DEVICE_MAX_WORK_GROUP_SIZE: 1024
[ 1 ] Intel(R) HD Graphics 530
        CL_DEVICE_TYPE: GPU
        CL_DEVICE_GLOBAL_MEM_SIZE: 6393515213
        CL_DEVICE_MAX_MEM_ALLOC_SIZE: 2147483647
        CL_DEVICE_MAX_WORK_GROUP_SIZE: 256

use cgminer it's for nvidia .
i don't know if there is a version of cgminer for ubuntu, but if it is copy skunkhas.cl from sgminer put in the kernel fil of cgminer and mine

Try to run this so we can see how many gpus does it recognize :

sgminer.exe -n
pause

It works but not fully optimized. Better than having nothing for Linux i guess :/

I test sgminer on intet IGP - HD 630. Hashrate is very low, from 300 to 400 kHash. There is an opportunity, there is no sense.