If you test during the hottest part of the day temps will differ from when you test at the coolest part of the night.
Has it been unusually hot in your area lately? That might have as much to do with higher temps than the TIM. You might not actually need to make changes.
For the Phenom II X4 either one works well.
Just don't use more on the crossed lines (a common error) than you do for the center pea.
With pressure of the heatsink and heat of operation the TIM will usually migrate to where it's needed.