New Build with PhenomIIX6, should I go for 1333 or 1600 DDR?

amec

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Hello,

I'm choosing the components for a new machine and I have a doubt about the memory to choose.
It seems that the mother-board supports 1600 modules, but only in O.C. (overclock?), so it says. I'm not really interested in overclocking, and I'd rather keep my system stable and cool, but if it's all automatic and safe I'd go for it.

So the question is: shoud I buy a 1333 or 1600 modules?

The configuration would be

- Asus M4A88T-M 880G
- Phenom II X6 1055T
? G-Skill 8GB (2x4GB) DDR3 1600Mhz RipjawsX Memory Kit CL9 (9-9-9-24) 1.5V ?
? G-Skill 8GB (2x4GB) DDR3 1333MHz RipjawsX Memory Kit CL9 (9-9-9-24) 1.5V ?

Thanks
 
Welcome to Tom's Forum! :)

Other than an ASUS MOBO equipped with DOCP** you would need to either OC the FSB -> 240MHz or CPU-NB Frequency -> 240MHz even on the 6-core for DDR3-1600.

So I would get the 2x4GB DDR3-1600 kit IF you're fine with making a few adjustments in the BIOS, otherwise by default the RAM is going to run DDR3-1333 SPD.

** I looked at the manual there's no DOCP setting so you'd have to OC as I mentioned above and manually set the CPU-NB Frequency, DRAM Frequency, DRAM Timing Mode (CAS Timings), Memory Voltage (for non 1.50v), etc.

Therefore, IMO for the most stable and easiest is a 2x4GB DDR3-1333 Kit and maybe one with CAS 8 e.g. 8-8-8-24 @ 1.50v. Further, with 4GB/stick density I recommend using the latest BIOS and using ASUS EZ Flash 2 for flash the BIOS; see -> http://www.tomshardware.com/forum/289507-30-what-flash
 

amec

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Thanks jaquith for the comprehensive answer,

I've only this option available under CL9:
- Kingston 8GB (2x4GB) DDR3 1333MHz HyperX Memory Kit CL7 1.65V

but still the voltage will need tweaking. Will the mobo boot if it's set by default at 1.5V?

What would you expect to be the performance boost of a CL7 vs CL9 @1333? 1%? 5%?


A.
 
Memory Over Voltage -> +0.10 to +0.15; +0.0 = 1.50v so 1.50v + 0.15 = 1.65v. The difference real world DDR3-1333 CAS 9 vs DDR3-1333 CAS 7 is about 1%~3% which is correct. So if you're rendering (10 minutes on a 2 hour job) or gaming (+3~6+ FPS).

First, see if there's a +0.15 setting in the BIOS with the Memory Over Voltage. Otherwise, get the DDR3-1333 CAS 9.
 

no1spank

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The AMD Phenom II has a 1333mhz memory controller so If you are not looking to play with any systen settings there won't be any benefit getting faster memory as the memory controller will be a bottle neck.

However if you don't mind clocking up the speed of the North Bridge on the motherboard to 2400mhz ideally then the system as a whole will benefit without overclocking anything else. It might be worth speeding up the HT link as well.

The rule of thumb for finding ideal NB speed is: Divide Mem Speed by 2 then X by 3. That is why stock NB speed is 2000mhz to match the processor memory controller.