PUMA 6 chipset / Need alternate modem/router combo

Hello, Currently renting an Arris DG2460A modem/router combo from Cox. Just switched from the Arris TG2472 (I think was the model). I am fully aware of the issues surrounding the PUMA 6 chipset with certain modem/routers. Last time I was in the Cox local store to try and get a different modem/router combo due to stutter/jitter every few seconds due to the faulty chipset, they were unaware of the issue. I explained what the problem with the chipset was, the gentleman that was helping me went to the back and pulled all the modem router combo's he had and said I could swap it out. But I ended up with another Arris that has the PUMA 6 x86 Atom faulty processor. I would like to get a swap to a NON-PUMA6 chipset modem/router combo that supports your 300/30 connection. Can you do an exchange on my rented modem for one that works or at least provide a list of Cox Ultimate speed supported modem/router combo's that DO NOT have the PUMA6 chipset in them?