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If you buy it without HDD or "erase in save mode" (= erase and rewrite it in random-mode completely 3-10 times) the old HDD/SSD (but that will take some hours depending on capacity) you will be safe. the most safe is to buy without drive and put in your old one or a new one.

in general, you are much more in danger if you SELL your equipment with your old HDD, because if you don´t erase definitely in REAL safe mode it is very easy to recover all your data.
I was talking about the USB3-ports expresscard.
 
The performance increase is significantly lower on the 2010 with SSD, compared to the 2011, because it's not SATA-3, but still well worth it.

http://www.ebay.com/itm/252034394010?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
This USB-3 card does not need 3rd party drivers - no drivers needed at all, and it's fast.

The previous card needed 3rd party drivers and was slow and unreliable detecting portable drives - I used a glue gun to secure it, and a soldering iron to release it making way for the new card.

https://forums.macrumors.com/threads/usb-3-0-expresscard.911141/page-5

What makes SSD lightning fast is not just transfer speed, but iops too.
 
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