I did a quick HD Tune benchmark run of one my recently purchased Western Digital Green 4TB drive.
HDTune 5.0 read benchmark of WD40EZRX drive
Compared to the 3TB drive that I used to own (and now sold), the sequential read speed has improved slightly (from 114MBps to 122MBps). However the access time has increased from 16.6ms to 17.1ms. You can check out the benchmarks of the 3TB drive, the WD30EZRX from this link.
Crystal Disk Mark 4.0.3 scores of WD40EZRX drive
The Crystal Mark scores aren’t comparable with the benchmark scores on that page due to version mismatch as well as the tests were performed on an partially filled drive. The HDTune results should be more appropriate.