Hello Kevlaur:
I use NG9. I do daily incremental image backup, but to local HDD, *NOT* NASLite+.
But for discussion sakes ... I just did a full (first) image backup of a 27.9GB partition with only 3.18GB used. A little slow in my opinion (8.5 minutes), but no problems. The compressed image was written to Disk-1 on NASLite+, while streaming MP3 from Disk-2. Size of compressed image: 3.11GB (the partition has compressed data). So, not taking into account overhead, etc to start the process, average speed is 6.24 MB/sec.
So,
actually, that's pretty good for a 100Mbps net, because that's a respectable write-speed based other posts showing performance in about this ballpark (and taking into account the other network activity).
One thing that I first thought was odd, and you should check in NG10 version. I first tried to save to "LOCAL FILE" using a
mapped-network drive (NASLite+ Disk-1). Since it's mapped in Windows Explorer I would expect that to work. But NG9 complained, as it detected it as non-local. NG9 forced me to use the "NETWORK FILE" option. In NG10 check to see if you can use either technique and if so, does it help make a difference.
You might want to check that SMART testing (every 5 minutes) is turned off, and that you are not writing to NASLite+ during the one-time initial post-powerup SMART Self-Test. It can impact peformance a bit.
If you are using the free NASLite, performance is slower, and SMART testing can not be turned off ... so that may be where the problem lies.
Hope this helps ... at least I was able to show NG9 & NASLite+ seems ok.

Georg