ReadyNAS NV+ Seems really slow

Despite Jumbo Frames supposedly being faster, I had a lot of problems with my NV+ and spent days mucking around and testing and eventually found that I was much better off just turning the darn Jumbo Frames off. I don't think there is any industry standard for Jumbo Frames and I believe that incompatibilities exist between specific devices. Here's my results:

PC & NV+
Jumbo Frames ON for both PC and NAS: Write = 16.4 MB/s, Read = 22.2 MB/s
Jumbo Frames OFF for both PC and NAS: Write = 22.2 MB/s, Read = non-responsively slow (due to switch having Jumbo Frames enabled)
Jumbo Frame OFF NAS, ON PC: Write = 22.2 MB/s, Read = 33.3 MB/s

MAC & NV+
Jumbo Frames ON for both Mac and NAS: Write = non-responsively slow, Read = 27.0 MB/s
Jumbo Frames OFF for both Mac and NAS: Write = 19.2 MB/s, Read = 23.8 MB/s
Jumbo Frame OFF NAS, ON Mac: Write = 18.9 MB/s, Read = 33.3 MB/s

Conclusion from my testing is that you will always get faster performance on the NV+ with Jumbo Frames turned off than you will with it turned on. Since I have another NAS that works fine with Jumbo Frames turned on, I tried to find a balance where I could have the rest of my network on Jumbo Frames (PC's, Switches and my other NAS) but leave the NV+ with Jumbo Frames off. I think the NV+ actually gets better performance if Jumbo frames is totally off but this slows down everything else for me.