Verified answer

If your computer can handle the 6Gbs, that is one consideration. You would also need to used Windows 64 bit to use the 6Gbs. 32 bit Windows will only allow 4 Gb and then not use all of that.

Speed wise, the 4 gb 1600 mhz would be faster.

And the way I understand it, unless you can use the memory, having more doesn't make it faster. For instance, let's say you had 4Gb, but your computer only uses 2.5 Gb most of the time while running. So, it will run 2.5 Gb and the other 1.5 will sit idle. You could have 10Gb and still only use 2.5 Gb, if that is all your computer is using.

But for more intensive work or gaming, you could probably use all of the 4Gb, or in the case of having the ability to use all 6Gb, you might need all that memory if you are doing some intensive work.

So, it depends. If you are just browsing the net, or checking email, or doing some light work, 4Gb is plenty, and at 1600 mhz, it will do great. That is ,if your computer is set up to use the 1600 mz. Some motherboards use it, but need to be overclocked in order to use the 1600 mhz. So under normal use, it might run at 800 mhz.

for your PC (see your Mhz) 4gb.

Fix your PNY issue lol and use the 6gb if you can later