1333 mhz ddr3 vs ddr3 1600 mhz

Purchase correct RAM from a vendor known to support Macs. Other than Apple there are only two that I have used and can recommend, Crucial and OWC / MacSales.

This OWC blog may interest you: http://blog.macsales.com/14262-boost-2011-mbp-performance-with-1600mhz-ram

Don't extrapolate that information to any other model Mac.

Macs are very particular about the RAM they like. In theory it should run that RAM at the slower speed your machine requires. In practice you may end up pulling your hair out in a month trying to figure out where your kernel panics are coming from.

Use the correct RAM for your specific model Mac. Anything other than that is incorrect and may not work.

Even if the speed difference alleged in the OWC link above is realized, it's a 2% increase. Upgrading from Mountain Lion to Mavericks alone on that same model MBP resulted in about the same performance increase, and it's free. Incorrect RAM may manifest itself in random crashes that can appear immediately or years from now, long after you have forgotten about having installed it.

BobRz wrote:

it's sure not going to run at the faster speed.

Actually in this case there will be a very modest performance increase due to the 1600MHz speed. To what degree will it be noticeable is an open question. I have a 2011 MBP and I am not about to install the faster RAM. 🙂

Ciao.

ali--1985 wrote:

I do agree with what you all saying but the thing that is confusing me is that the 1600 mhz elpida is actually from a later macbook pro model as i am buying it from a friend that has just upgraded to 2x8 on his so thats why i thought it would work

You will not hurt your MBP trying it. It may work it may not. I have experimented installing RAM from a 2011 MBP into a 2010 MBP. In that case that RAM worked but was down clocked.

Ciao.

BobRz wrote:

The problem to me is it may work sometimes. Meaning it may panic sometimes too. I just don't see the benefit unless it's free.

Yes, point well taken, and there could be other factors that might cause problems. I have yet to hear of a MBP be destroyed by incompatible RAM, they just don't operate correctly thus no harm experimenting.

Ciao.

This is an old thread but there is no question that 1600 mhz OWC ram will run at 1600 mhz resulting in about twenty percent faster memory and an over all system sytem, speed increase of around 3 percent. This is documented. So it is probably not worth it if you already have 16 gb of 1333 but, if a stick goes bad, why not use 1600?

It has been my experience that putting faster RAM into a Mac generally results in the RAM clocking down in speed to match the Mac if it works at all. If you check into the functioning of the MMU, you will find that is exactly what it does.

As sensitive as Mac are to the RAM that is installed in them I strongly recommend against using that RAM in this Mac.

You are just plain wrong in this case. The chipset supports 1333 or 1600 mhz ram. It does not down clock. It runs faster in real world benchmarks.

http://blog.macsales.com/14262-boost-2011-mbp-performance-with-1600mhz-ram

It also runs faster on Geekbench.

That is not what I read on how the MMU operates. It appears to me to say that it is capable of running at a fixed speed and downgrades RAM to match that speed if possible. Otherwise it doesn't operate at all.

I have no idea, I just understand how MMUs work and they are limited to a set clock speed for RAM. If RAM that is capable being clocked faster is installed then the clocking of the MMU slows it down or the RAM fails to work. it is that simple.

I do understand. THE MMU is part of the chipset. The chip set's datasheets say that it supports both speeds. It supports both speeds. (remember Apple also told us the chipset only supported 8 gb of ram). When in doubt, the Intel data should be considered correct by default. *

*16 gb even upped the video memory available to the HD Graphics3000 to 512 because that was built into the chipset as a percentage of total ram.