ssd running slow

Typical lower-end Kingston SSDNOW SSDs are rated for 6,000 read IOPS. Yours is rated for 3,300 read IOPS. A 4KB read is 4,096 bytes. So 12.33MB/s is 12.33*1024*1024/(4*1024) IOPS, or 3,156. So that seems reasonable.

Evidently the Kingston SSDNow V+ 100 256GB and SSDNow V 100 256GB provide quite poor NCQ performance, as they suffered when running the CrystalDiskMark random read 4K-QD32 test. This was also a weakness of the original SSDNow V 128GB drive. Whereas the old OCZ Vertex 120GB provided a throughput of 65MB/s, the SSDNow V+ 100 256GB was limited to just 19.9MB/s.

The random write 4K-QD32 performance was slightly better as the Kingston SSDNow V+ 100 256GB achieved a throughput of 37.1MB/s while the SSDNow V 100 256GB managed 28.4MB/s, which was a considerable improvement over the 11.4MB/s of the SSDNow V 128GB drive. - Review

Two things immediately leap to mind.

The first is as psusi already mentioned that the drive is really full. Besides the impact on write performance you suffer from the lack free blocks psusi talks about, there are two other effects as well. With a large drive like that, full to the brim, the FTL table will be huge so doing look-ups in it will be slow. This can be part of the explanation for the low 4k score. Also, with that little space Windows will start having problems with fitting in temporary files and such. You really need to free up space one way or another.

The other this is that I suspect your SATA controller is in IDE emulation mode. This means you don't get NCQ which will hurt performance, especially the 4k QD32 numbers. A telltale sign of this is that the 4k and 4k QD32 numbers are essentially the same.