HELP ! SD card is doing my skull in - this is a strange one !

Trouble with sd card in tablet so decided to check it out in my Win 7 computer.
I have 4 new sd cards 32gb and 64gb. I have 2 new SD card readers - USB 3
I have 9 mp4 video files on my hard drive and all play perfectly with WMP
ok here is the problem:
When I copy these files to my SD cards (any of them), the first 3 files will play from the the sd cards but the other files are unusabe though present. The info pane at the foot of windows exporer shows no "data rate" etc details on the files that will not play
INFO:

I have tried formatting the sd cards FAT32 and EXFAT and NTFS.... I can play the three good files from any of these file systems
The three good files are the first 3 to be copied. If I copy A -B-C first then they are good and the other are not

IF I copy C_D_E first, then these are good but the others are not
File sizes are all under 4gb individually but about 4GB for 3 files

I am aware of the 4GB limit for FAT32 so I used the other formats too

Question :
Is there some kind of limit under win 7 pro 32bit, that will not allow more than 4gig of movie files on a SD card ? The cards have been in my android (aagh) but I used diskpart to clean them and re-write the MBR and single partition
The android can play the same files that win 7 can play, so if I can get win7 to read and play videos from the sd, I am confident the tablet will play them.
I was surprised, that when I format NTFS, the tablet can read the sd card and play the 3 movies ! .. But it can

Help ! I have spend 4 days trying all these various options and now I am well and truly stuck. 4 new sd cards various types, 2 new usb3 card readers, a great win7 system and a new tablet...

strollin said:

Are these by any chance Sandisk cards bought on Ebay? I read somewhere that there was a rash of counterfeit Sandisk cards being sold there.

I got two of those first--those hot 64gb's
piece of junk
their max write speed with either of my usb 3 card readers was 6mbs !
sent em back and got a refund
these other 3 cards I am using are also off ebay but 3 different sources and different sizes and different brands and different classes...

I spend the first 2 days thinking it was the "android lock sd card" thing, until I tried playing the movies off my sd card in the computer and realized the problem was nothing to do with the tablet. Then I thought there was some sneaky android lock in the mbr of the cards when I had them in the tablet, so I went to command prompt in win 7 and did the clear and MBR reinstate while the card was in my card reader. As it can be different files that will not play, and as I can get those files to play by copying them first, I think there must be some kind of limit at around 4gb that I am hitting (even when formatted exfat or ntfs). I have even tried creating separate folders for each file, and it still hits a TOTAL limit of about 4gigs (or 4 files) for good files that will play... It will copy any number of files but only the first few play

aaaghhh !

Check all your pen drives with H2testw Test for Fake USB Flash Drives ? H2testw | Portable USB Applications

You may also do a google search "testing fake pen drives"

Thanks I will have a go ...To buy 6 different sd cards from 5 different vendors and have 6 fakes, would be....unfortunate. I will check em... Could codecs work on the regular drives, but not the SD cards ?

Guys, I think you are barking up the right tree. I used 'fakeflash' to check the SDs and they are definitely defective and hold only a few gigs instead of 64. I found it hard to believe that ALL sd's from ebay are fake - but the evidence is in and 4 out of 4 tested are fake. Different vendors, different capacities, different classes. I paid $17 to $19 each for them and sandisk's website is selling them for $125 !!! If its too good to be true... Anyway that's 5 days of my life I am not getting back even if I get the refund. I have headache now. Thanks folks.

ps--more info: the full size sd card that has always behaved perfectly was the only one that passed the 'FAKEFLASH' quick utility test.. I have just been down to Target and bought a class 10, 32gb micro sd ($26) and put it through that test - and it too passed. I just copied 11 movies to it and put the card in my Asus Android - I can play them all no problem for the very first time ! I have two returns done with ebay and 3 pending approval. I have seen websites that say ALL micro SD cards on ebay are fake (my single full size is excellent). From my sample of FIVE cards, that is 100% true....

pps -the two Sandisk 64gbs were refunded within 30 minutes of my return request. And then.. I just received the Sandisk micro SDs back USPS ----and they are marked "address unknown" even though I used the ebay pre-printed label... Fake SD's sold from a fake address ! Put em in my 'fakechecker' and it went nuts and then 'bricked' em...