We want to use a pair of juniper qfx3500 in virtual chassis mode and we have around 1000x SVI with 7 bgp peer and no full table and around 20gbps bps and 8m pps, can qfx3500 handle this amount of traffic with no impact on cpu ? my mean is 1000x SVI does not impact on cpu performance? Thanks
All the parameters you give are within the scaling capabilities of the QFX3500.
However, in several of your previous posts asking about equipment capabilities to meet your scaling needs, you later follow up asking if you can add ACLs or PBR. Those will be a problem for the QFX3500. It has an unusually small TCAM allocation for ACL -- only a few hundred entries IIRC -- and probably won't suit similar use-cases that you've asked about previously.
I wouldn't recommend virtual chassis / QFabric mode of operation on QFX3500. It's just my opinion, but the benefits never outweighed the increased bugs / malfunctions on this particular series.
Also, I'm not sure what the licensing requirements are for QFX3500 with BGP. You might need to buy something like Advanced Feature License which may make the switch a bigger investment than it's really worth, as compared to something slightly newer like a QFX5100/QFX5200 series.