1. A HDD light may help you diagnose the problem. But it won't help or hurt performance.
2. I don't think adding more RAM will help, unless you take advantage of the added RAM by disabling virtual memory at the same time. But also I think that VM is disabled by default, anyway. A new SSD
may help, but as you know, they can be expensive.
3. SD card won't make a difference in any fashion.
4. OSX or Windows 7 may help, I don't know.
5. The Mini 10 is inferior to the 9 in many ways, I'd avoid it. The Mini 10v is virtually identical to the Mini 9, aside from the change to a standard laptop drive (SSD
or HDD), instead of the Mini 9's tiny SSD
. I don't know how prone the 10v's SSDs are to stuttering. A 10v with a standard hard drive should be fine.
But in the end, I think software makes a big difference. I've spent some effort tuning my Mini 9 with the slow 4GB STEC SSD
running Linux, and I've been very happy with the speed.