So there are coupe of things---usually the key one to look at is D2 in which case risperidone would be slightly higher---normally that's the most important one. The thing is this is just the known interactions---there is something with clozapine that affects NMDA function and at high doses same for olanzapine----olanzapine was supposed to be like clozapine but without the side effect of death. But just based on what is in the chart for those two I would be suspicious that the 5HT7 was the difference. Some of the new ones like latuda also have that 5HT7 which is one of the serotonin receptors and there is some association of 5ht7 with sz. Its not really known exactly what is going on with that because it should really be affecting mood but there is a tie in with 5ht7 and glutamate. The reality is at some point people are going to have to do this based on genetics for anyone to figure out what is really going on. Here is a reference where 5ht7 activity is affecting glutamate by regulating the metabotropic glutamate receptors which will in turn affect NMDA function...since its an antagonist it would be doing the opposite of what this paper is talking about...

Activation of 5-HT7 serotonin receptors reve... [Biol Psychiatry. 2012] - PubMed - NCBI

The primary reason I put this up wasn't actually for effectiveness so much as side effect profiles---if you click yes on some of the actual charts you can see the side effects with each receptor binding. The only one that's clearly been linked to effectiveness for positive symptoms is the D2 though....for now....