If by “Silva” you mean Anderson, GSP’s level of competition is significantly higher.
Here's some real numbers for Silva's opponents. I took 11 fights in his division and left out the two rematches vs Franklin and Sonnen, using their stats from the first time they fought. The times each person has been finished is in parenthesis next to their overall record when they faced Silva:
Leben: 15-1 (0)
Franklin: 22-1 (1)
Lutter: 8-3 (2)
Marquardt: 25-7 (2)
Henderson: 22-7 (2)
Cote: 13-5 (2)
Leites: 14-1 (0)
Maia: 12-1 (1)
Sonnen: 25-11 (10)****
Belfort: 19-8 (3)
Okami: 26-5 (1)
Total: 201-50 (24)
You can see that Chael Sonnen accounts for almost 50% of the overall number of finishes from all 11 opponents, and over 20% of their losses. I'll do GSP's opponents next and post it shortly, using 11 fights at 170, leaving out rematches if applicaple, and using the data from their first match only.
GSP's opponents at the time they fought. I went from the first Koscheck fight to Hendricks, also 11 fights. These are fights in the WW division only, and the only rematch during this time was Koscheck, so I skipped their second fight and used the data from the first fight only. The Hughes and Penn fights are from the fights during this time period, not their first fights:
Koscheck: 9-1 (1)
Hughes: 42-5 (5)
Serra: 10-4 (1)
Fitch: 19-2 (2)
Penn: 13-4 (1)
Alves: 17-5 (4)
Hardy: 23-6 (3)
Shields: 26-4 (1)
Condit: 28-5 (3)
Diaz: 26-8 (2)
Hendricks: 15-1 (0)
Totals: 228-45 (23)
Things to consider:
-Sonnen's losses and times finished sways the numbers absurdly, accounting for 22% of the total losses and 41.66% of the total times finished. Hughes' wins sway the win column absurdly, accounting for 18.42% of the total wins.
-Silva's opponents had a slightly lower win percentage overall despite the giant boost from Hughes, and were finished (minus Sonnen) almost 50% less.
-2 out of 11 of Silva's opponents never won a championship prior to fighting him: Leites and Okami
-4 out of 11 of GSP's opponents never won a championship prior to fighting him: Koscheck, Fitch, Alves, and Hendricks. This number would be 5 if GSP hadn't previously lost his championship to Matt Serra.
Silva fought 4 guys with only 1 previous career loss
GSP fought 2 guys with only 1 previous career loss
Silva finished 9 out of 11 of his opponents. 81.81%
GSP finished 2 out of 11 of his opponents. 18.18%
Another fun fact about GSP's "strength of schedule" or "quality of opposition" is that he had 9 fights against the same 4 people, 2 of those 4 people spent the majority of their career at LW. If his division was so absurdly stacked and the competition was so deep, why so many rematches?
26-2 is a 92.85% win rate with a 54% finish rate- going 7-2 against the same 4 guys - 26.92% of his wins were against 4 people.
33-4 is 89.19% win rate with a 78.79% finish rate - going 4-0 against the same 2 guys - 11.76% of his wins against 2 people.