A nice mix of DDR3 #### (PC3 #####) ?

mukarakaplan

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My system has 4gb mem. Specifications of the mem are below.

G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Dual Channel Kit Desktop Memory Model F3-10666CL8D-4GBHK
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231189

Now I wanna buy 4gb more. Should the new 4gb's specifications for the DDR3 #### (PC3 #####) match the old one's or not?

Say, would the following work well with my current system?

G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9D-4GBRL
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231277

OR

G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL7D-4GBRM
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231303

 
You should match your existing RAM: F3-10666CL8D-4GBHK (1333MHz, latencies 8-8-8-21), if you can, or just buy all new RAM.

The F3-12800CL9D-4GBRL is 1600MHz with latencies of 9-9-9-24.
The F3-12800CL7D-4GBRM is 1600MHz with latencies of 8-8-8-21.

If you buy one of those, you will have to adjust your latencies in the BIOS to meet your least powerful RAM: 1333MHz with 8-8-8-21 (your existing RAM).

And populating all the DIMM slots will likely require that you reduce your RAM speed still further, maybe to 10666MHz to get them to POST.
 

mukarakaplan

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Would the speed change significantly if I start using 8g of 1600, 9-9-9-24 (or the fastest whichever it is), instead of 8g of 1333 with 8-8-8-21? I mean they are for almost the same price, so if the speed changes much, then I would sell my 4g, and buy 8b of the faster ones.
 
There are two trains of thought on this, the first is that high speed DIMM's can make up for running slower timings by the amount of bandwidth provide the processor. Specifically, bandwidth is the amount of data that can be moved from one given device to another.
The other point of view is that memory with low latency can make up for the lack of bandwidth because the memory has a lower latency that in effect moves data between the CPU and memory faster. Programs that do not require a large amount of bandwidth tend to benefit more from quicker data transfers between the memory and the rest of the computer; such as games or 3D applications.
 

mukarakaplan

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My processor is AMD Phenom II X4 965, 3.42 GHz, which has a 7.4 Win7 experience index score. But I think the memory I currently have cannot support it well (5.9 index score). I generally run a statistical software analyzing huge data sets, and my computer almost freezes while the software runs, and it takes a lot of time to get the result. That's why I thought that I need to spend some money on memory, but I just want the best match.