Some great new upgrades to the 7420 were announced and released today. You can now get 10-core CPUs in your 7420, allowing you to have 40 cores in each controller. Even better, you can now also go to a huge 1TB of DRAM for your L1ARC in each controller, using the new 16GB DRAM modules.
So your new choices for the new 7420 hardware are 4 x 8-core or 4 x 10-core models. Oracle is no longer going to sell the 2 x CPU models, and they are also going to stop selling the 6-core CPUs, both as of May 31st. Also, you can now order 8GB or 16GB modules, meaning that the minimum amount of memory is now 128GB, and can go to 1TB in each controller. No more 64GB, as the 4GB module has also been phased out (starting today, actually).
Now before you get upset that you can no longer get the 2-CPU model, be aware that there was also a price drop, so that the 4 x 8-core CPU model is a tad LESS then the old 2 x 8-core CPU model. So stop complaining.
It's the DRAM that I'm most excited about. I don't have a single ZFSSA client that I know of that has a CPU bottleneck. So the extra cores are great, but not amazing. What I really like is that my L1ARC can now be a whole 1TB. That's crazy, and will be able to drive some fantastic workloads. I can now place your whole, say 800GB, database entirely in DRAM cache, and not even have to go to the L2ARC on SSDs in order to hit 99% of your reads. That's sweet.