Patanjali, you’re missing one thing here:
Higher QDs enable parallelization, because an SSD controller can then access multiple flash chips at once.
Here my Samsung 840 Pro benchmark values (NOT my RAID - this is my boot & software disk):
core (samsung 840 pro, 256 mb @ sata III)
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CrystalDiskMark 3.0.3 x64 (C) 2007-2013 hiyohiyo
Crystal Dew World : http://crystalmark.info/
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* MB/s = 1,000,000 byte/s [SATA/300 = 300,000,000 byte/s]
Sequential Read : 516.964 MB/s
Sequential Write : 487.559 MB/s
Random Read 512KB : 443.380 MB/s
Random Write 512KB : 464.603 MB/s
Random Read 4KB (QD=1) : 33.631 MB/s [ 8210.6 IOPS]
Random Write 4KB (QD=1) : 95.699 MB/s [ 23363.9 IOPS]
Random Read 4KB (QD=32) : 259.869 MB/s [ 63444.6 IOPS]
Random Write 4KB (QD=32) : 273.092 MB/s [ 66672.9 IOPS]
Test : 1000 MB [C: 49.2% (105.2/214.0 GB)] (x5)
Date : 2014/07/26 16:52:24
OS : Windows 8.1 Pro [6.3 Build 9600] (x64)
It escapes me why there is still software around which only fetches multiple files in a single thread, because this is a well known fact, but I blame it on the Morts.