Time Machine Slow in 6.9.2

 Hi All - Brand spanking new 426 - Currently 3 WD Red 4Tb disks in while I get myself configured. I installed 6.9.2 first thing out of the box last night and left it partitioning overnight.  First thing I set running was Time Machine. I set myself up 2 personal partitions. One is 500Mb and one is 1Tb to match the needs of the two machines. Started this at 0800 and it's now 1800 and the 1Tb machine has got 9Gb in. The 500Gb machine has managed 18Gb. I'm running a 300Gb data transfer concurrently from the old NAS and this is running at 4Mb/s so I'm not exactly stressing the machine as no one else is accessing it. Everything is CAT 6 hooked up to 1Gig Netgear switches and all on the same internal 192.168.20.x subnet. I've set the OSX optimisation in SMB settings. Any helpful suggestions - this is going to take about 10 days to back up at this rate...