ARMv6 is very similar in all regards to ARMv7 and there are very fast implementations available. Are you talking about ARMv5 perhaps, which has a terrible memo

ARMv6 is very similar in all regards to ARMv7 and there are very fast implementations available. Are you talking about ARMv5 perhaps, which has a terrible memory model making fast multitasking implementations with memory isolation very hard to implement? ARMv7 just adds some new instructions which are while usefu, does not give the performance benefits.