I have accumulated DNA segment match information from ftDNA, GEDmatch, and MyHeritage.  It is just recently that I've added MyHeritage DNA donors data, and I've found that the SNPs are two to four times the value of GEDmatch and ftDNA (when comparing the same donors). Does anyone know the reason for this substantial difference?

Below is a one example of many... (sorry, I don't know how to format the tables)

From GEDmatch.com:  
Chr	Start Location	End Location	 cM	   SNPs  
3	    23,760,064	  29,187,906	6.2   	931  
8	    29,331,698	  67,590,346   26.4	  3,836 

From ftDNA:  
Chr	Start Location	End Location	 cM	    SNPs  
3	      24060170	    29187906	7.05	 856  
8	      29450700	    68699024   25.84	3622  

From MyHeritage:  
Chr	Start Location	End Location	cM	    SNPs  
3	      24039380	    29154358	 7	    2944  
8	      29272247	    67933838	26.3   14848