30% is nice, but for applications like backups it's not enough by a long shot.
My experience is that the average data stream in such instances gets 1.2-1.7:1 compression using gzip and ends up limited to an output rate of 30-60Mb/s (this is across a wide range of modern (circa 2010-2012) medium-high-end CPUs.
The limitation here is usually the speed at which data can be fed into the CPU itself.
Unfortunately, in order to keep a LTO5 tape drive happy, it needs a raw (uncompressable) data rate of around 160Mb/s. If fed compressable data it requires even faster data rates.
LTO compression is clearly a lot faster, but somewhat inefficient (equivalent to gzip -1 - it's good enough for most purposes). LTO4 drives and upwards usually have built in AES-256 encryption engines which can also maintain these kinds of speeds.
What this means for my case is that I'd need a 400% or better impreovement in order to consider it worthwhile.
Similar considerations apply across LANs. At 30Mb/s, compression is a hinderance on Gb-class networks and the question is whether to spend more on networking or on compression... :)
