ok so the 840 pro 128 gb flavor is 125$
and the 840 250 gb flavor is 160$
will the 840 pro be alot faster or should i just get the 840 for the extra memory?
The Pro uses a different type of NAND flash which is both longer lasting, and faster. The non pro would suffice in a gaming rig, if you wanted the extra capacity at a similar price point. However, you could get the faster Pro SSD, and then add more SSDs at a later time.
You don't necessarily need the write speed on the Pro, but it is advisable to get the higher quality NAND flash, for a longer lasting drive.
The 840 actually uses a newer TLC NAND, whereas the 840 Pro uses an older, but actually faster MLC NAND. They are almost identical in write speeds, but the 840 Pro pulls ahead, noticably, in reads, making it a great option for a boot drive. You can get a much larger capacity 840 for just a little bit more than the 840 Pro, as in a 500GB 840 for $80 more than a 256GB 840 Pro. I'd get the 840 Pro if you can afford it, the 830 if you want a more balanced drive than the 840, and the 840 if you want massive amounts of storage.
Shush, Brennan. I got this one! ;)