The spec I saw was 2x 64-bit (8 with hyperthreading) for both 2220 and 2240... same controller module just different max spindles (60 compared to 144) and mezz card for FC or 10GbE on the 2240 (but heard we may get a mezz card option on the 2220 for ethernet).
It has a different chassis… looks like the same PCM… the chassis for 2220 is a different drive type. Performance should be the same for the same spindle count.