What is different with these 2 SSD's

I'm not sure what is different with these 2 drives, anyone know?

http://www.amazon.com/OCZ-Technology-2-5-Inch-Industrys-Warranty/dp/B007RARIF6/ref=sr_1_3?ie=UTF8&qid=1353360571&sr=8-3&keywords=vertex+4

 

 

http://www.amazon.com/OCZ-Industrys-Performance-2-5-Inch-Warranty/dp/B008MIJOTK/ref=sr_1_4?ie=UTF8&qid=1353360571&sr=8-4&keywords=vertex+4

Probably different amazon sellers?

it says they're both shipped and sold by Amazon.com 

One is much faster than the other, ya have to read the specs to find out what the differences are...

yes i did read the specs.  The more expensive drive has slower write speeds by 30mb/s and slower reads by 25mb/s the 4k read iops are slower as well...as it looks like they're both sold and shipped by amazon it puzzles me as to why the other drive is that much more expensive.

the cheaper one (with the m)has micron-made nand chips, and is slightly slower, but not significantly

http://www.ocztechnologyforum.com/forum/showthread.php?104206-Vertex-4-model-VTX4-25SAT3-512G-M