G.skill f3-2400c11d-8gxm

[hyperspaced]

Hello,

I am considering buying 2 kits of this memory G.SKILL F3-2400C11D-8GXM at 2400MHz, for a total of 16GB (4x4GB).

1) Is it compatible to my Z77 Asrock Pro4-M + Intel i5 3570K ?

2) I am planning to run this memory at 2133MHz in order to tighten up the latencies and reduce the stress on the IMC. Is it a good practice?

3) I keep reading in forums that using 4x4GB memory puts a stress on the IMC. Can someone explain technically why this happens? As far as I can imagine, accessing RAM using 2 (dual) channels would be less stressing as the load is shared.

4) How do I ensure that the 2 kits I buy are "factory-matched" ?

Thanks!

[emissary42]

1) It probably is (with all Core i5/i7 Ivy Bridge & Haswell Setups)
2) I would then buy a DDR3-2133 CL9 kit right away. With a 2400 kit you have to guess the right timings for 2133 in the first place, unless you really know what you do. If you have fun spending some days tweaking and testing however, go for it and save some bucks.
3) Even with two modules you are usually saturating all two channels of the IMC. Thats why it is called Dual Channel. When you add another two sticks, the load (= "stress") per channel doubles.
4) Just buy the matching 4x4gb kit --> G.SKILL RipjawsX F3-2400C11Q-16GXM

I tested my own kit for DDR3-2133 and ended up at 10-11-10-27 1T 1.53V but went for DDR3-2666 CL12 in the end

[hyperspaced]

Hello emissary, thanks for the reply.

1) It probably is (with all Core i5/i7 Ivy Bridge & Haswell Setups)

a) Where is the probability located? I read the specs on my 3570K and it says it supports memory up to 2800MHz (overclocked), so is the motherboard. Is there a chance I won't be able to get 2400MHz out of the system?

2) I would then buy a DDR3-2133 CL9 kit right away. With a 2400 kit you have to guess the right timings for 2133 in the first place, unless you really know what you do. If you have fun spending some days tweaking and testing however, go for it and save some bucks.
3) I keep reading in forums that using 4x4GB memory puts a stress on the IMC. Can someone explain technically why this happens? As far as I can imagine, accessing RAM using 2 (dual) channels would be less stressing as the load is shared.
4) How do I ensure that the 2 kits I buy are "factory-matched" ?

I found the 2400MHz kit (2x4GB) in a super-deal, but I do need 16GB on my system, so I have to buy 2 kits.

b) Can't I use the XMP profile from the Quad-module kit as a basis on the 2 kits and relax the timings a bit ?
c) Also, will I have to boost the voltage of the IMC as well ?
d) How well do motherboards configure the settings if I leave everything on Auto ?
e) What exactly is "factory-matching" ? How can 2 kits from the same "batch" not be "matched" ?
f) Suppose that I buy only 1 memory kit. Will it work if I mix it with a 1600MHz CL-9 g.skill memory kit (run everything @1600MHz) ?

( Sorry for the myriad questions :-) )

[emissary42]

Where is the probability located?

I personally will not guarantee compatibility. I am not a G.SKILL employee, just a memory dude and overclocker.

I read the specs on my 3570K and it says it supports memory up to 2800MHz (overclocked), so is the motherboard. Is there a chance I won't be able to get 2400MHz out of the system?

Actually most 3570K won't do DDR3-2800 stable, but some can. With an 3770K the chances are a little better already and with a 4670K or 4770K almost any cpu can do it. Motherboard vendors however do advertise the fastest memory speeds their mainboards are capable of. That does not guarantee your cpu is capable of that clocks as well (the memory controller is inside the cpu, not located on the mainboard).

In general almost all 3570K should hit DDR3-2400 with ease. There might be exceptions, but i'd call them rare ones.

I found the 2400MHz kit (2x4GB) in a super-deal, but I do need 16GB on my system, so I have to buy 2 kits.

The mentioned quad kit (F3-2400C11Q-16GXM) should be a similarly good deal and is tested to work at specified timings with all four modules. Here in my country you can actually save some € with it vs buying the dual kits.

Can't I use the XMP profile from the Quad-module kit as a basis on the 2 kits and relax the timings a bit ?

Yes, you can. Do you want to?

c) Also, will I have to boost the voltage of the IMC as well?

Depends on your cpu. A decent mainboard will probably auto adjust VCCIO and VCCIO, a bad one will go way overboard with it

How well do motherboards configure the settings if I leave everything on Auto?

For lower speeds most boards do a good job. The higher the memory clock the worse it gets, esp. the voltages get really crazy really fast if left on auto (on most overclocking models).

What exactly is "factory-matching"? How can 2 kits from the same "batch" not be "matched"?

If you buy a kit, it is guaranteed to run at its specifications. However if you buy two kits, even of the same model, they are not guaranteed to work together at their shared specifications. Of course sometimes / often it works out, but if you don't want to fiddle with timings and voltages just buy the quad kit.

Suppose that I buy only 1 memory kit. Will it work if I mix it with a 1600MHz CL-9 g.skill memory kit (run everything @1600MHz)?

Mixing memories always carries a bit of risk of instability, even at low speeds.

[hyperspaced]

Thank you very much for your answers.