@nox 8K n/m from a 750ti doesn't sound too bad, honestly. Speed of the drive might also be capping the throughput.
@Havoc As haitch mentioned, plotting in direct mode doesn't measure nonces/minute accurately until the entire plot is done, which does make it difficult to figure out throughput. I usually do a small plot in buffered mode to get a general idea first.
My specs:
FX-8350 4.4GHz / 16GB / GTX 1070 8GB
devices.txt = 0 0 4096 512 128
:: Dual 500GB plots with 2.5GB stagger
gpuPlotGenerator generate direct E://Burst/plots/10105409137940147041_0_1904640_10240 F://Burst/plots/10105409137940147041_19046400_1904640_10240
:: Single 500GB plot with 5GB stagger
gpuPlotGenerator generate direct G://Burst/plots/10105409137940147041_99041280_1904640_20480
Also, be sure open up resource monitor to see what kind of disk write speeds you're getting. I was getting 20MB/s on a Seagate 'archive' drive and so naturally my nonces/minute dropped way down. Thankfully, I realized my mistake early and returned the drive and bought a proper NAS drive instead.