I just read writing out direct to disk setting may solve my issue wondering if any other options may work.
Recompressing video is very CPU intensive.
Direct-to-disk recording does not recompress video. Therefore it is not CPU intensive.
Try recording direct-to-disk before looking for alternatives. You'll maintain original video quality and reduce your CPU usage.
It's also worth noting that even at 90% it shouldn't be crashing regularly. Do you have it in a cupboard by any chance? sounds like it's either poorly ventilated or using a heatsink without a fan.
An SSD won't help significantly with your CPU usage because he hard drive is not the bottleneck. Recompressing video is. Waste of an SSD unless the HDD is a bottleneck. And it isn't likely to be with one camera.
I have a 3MP (2688x1520 @ 20FPS) camera running on an old Pentium E5300 system and it's only hitting 50% CPU utilization.
Personally it drives me crazy that to get BI to work you have to dial things down or replace an entire machine instead of just adding hardware. But it is what it is.