Pendrives slow writing speed

Evening:

I have a very strange flashdrive problem occurring. Just over a week ago, I noticed the 'write" speed on a Kingston DT101 16Gb 2.0 pendrive was less than half what it normally was. I went to the "net" and a few forums and after many attempts at repairing the drive, we concluded it was dying. I was resigned to that until yesterday when 2 other pendrives obtained the same anomaly. All 3 drives suddenly acting up in the same manner. NOPE! Something's amiss.

These drives are aprox. 2 y/o. 1y/o and 8mos. respectively. The Kingston is 2.0 and the others are 3.0. All have had "write" speeds significantly reduced and the Kingston is the worse. I transferred a file (360mb) today, just to "test" it and it started @ 268 kb/s and gradually rose to 1.6 mb/s. I have deleted/rebuilt it's partition, reformatted both quick and standard, run chkdisk, gparted, fsdsk and implemented some of their "repair"/fix tools. All drives have been run through virus/malware checks, file checks, and (Win7) comp>right-click device>properties>tools>error-checking; all tests claim drive are "healthy" and/or in proper working order.(???) Well, we know that can't be. OK,

So here's what I want to do;

#1. Identify and correct whatever is causing the drives to write so slowly

#2 Restore drive to original specs (hopefully). If you want to know what all I've done to the Kingston please request for it is an extensive list! Now, the specs: [Kingston DT101 2.0 16Gb~original write speed 5.8+Mb/s] Sandisk Cruzer 3.0 8Gb~ original write speed 14.5-18+Mb/s] [Sandisk Cruzer Glide 3.0 256Gb~original write speed 17-22+Mb/s] ((Dell Optiplex 9020-Intel i5)) ((MSWin 7 Enterprise)) The transfer out rates of all drives have not been affected(as far as I can tell). Has anyone even heard of such a problem?

Oh, those who want to say "the drives are toast, go get new ones" DON"T even reply to this thread. I, nor anyone else here needs/wants that ignorance.
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