Shri Vishnu is supreme Paramatma

There is only Narayana as supreme entity and there is none equal or greater than him.

So what is the difference that exists between Soul/Atman and Paramatma ?

1. ParamaAtman is swatantra Independent , Atman is dependent paratantra. He is dependent on God for all his activites ,happiness ,bliss etc.
2. Paramatma is all pervading ,he does not have limitation in space.Atma  is limited in size ,it is of the size of 1/millionth part of edge of a single strand  horse's tail hair. [anurupa]
3. Paramatma exists at all times  in a same poornaavastha, Atman comes into this world after he is woken to srujya avastha by paramatma ,hence he has apoorna.
4. Paramatma gyana is infinite , Atman gyana is finite.
5. Paramatma does not undergo any organic changes in his body .Atman acquires a body and undrgoes organic changes of this body.
6. These changes bring about changes in the anubhuti of the Atman in realising self , Paramatma's anubhuti is not different from him.
7. Atman is either stree or Purusha [male or female] ,Paramatma is both male as well as female.
8. Atman as a male is dependent on Paramatma and female Atman for its sukha[ happiness] , Paramatma is swarata ,He enjoys his own rupas  ,His Narayani female rupa is present in the Laxmi devi and He gives happiness to her through this rupa with his Purusha rupa.
9. Atman undergoes Samsara [ life cycle of birh and deaths] Paramatma is never born nor dies.
10. Atman has to do sadhana to achieve its realisation of self ,Paramatma has no binding onto himself ,he has Achintyaadbhut Shakti[ making impossible possible]

krishnarpanamastu