mixed vcf throughout

Hi,

In a mixed VCF environment:

2 Spine QFX5100

3 leaf QFX5100

3 leaf EX4300

What are the Layer2/Layer3 maximum performance expected to be reached in a mixed environment ?

The one reached by QFX5100 or the one reached by EX4300 or something else ?

I imagine that if traffic enters on QFX and exits on QFX the performance are the one from QFX, if enter on QFX and exit on EX the performance are the one from EX.

For performance I mean max throughput, max switching capacity, maximum supported routes, etc..

Am I correct ?

Any reference url or experience ?

Thank you in advance

bye