What is the difference between the CM238, CM236, Mobile HM175 Express Chipsets?

I've been seeing this a lot with MSI laptops and each series had different chipset, so what is the difference and how does it affect performance?

 

Intel's Ark information site provides lots of details on all their past and present components, some future stuff too, and you can add items into a comparison chart to see differences.

https://ark.intel.com/compare/90593,98085,98087

These are IO type motherboard chipsets, and therefore as long as the computer using them has all the IO support it needs for the plug holes it offers, you don't gain anything in CPU / GPU performance from one motherboard chipset over another.

In the single GPU GT73 the HM175 seems well suited, and there isn't any advantage added by using a CM238/CM236.

The added PCI lanes of the CM238/CM236 are really only needed in the SLI configuration GT73 / GT75, but MSI started out originally including them in all models, then someone figured out it was overkill in the single GPU models, and so today all of those have the HM175.

Cost savings in this case doesn't reduce functionality, unlike what happened between the GT72S and GT72VR generations.

 

Thanks @hmscott, this explains it all. That leaves me to choose any of the GT series without thinking about the chipset.