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Rad Community Technical Discussion Boards (Computer Hardware + PC Software) >> PC Hardware + Software (except Cloning programs) >> Corsair Memory with BEMP
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Message started by Christer on Jun 15th, 2010 at 7:35am

Title: Corsair Memory with BEMP
Post by Christer on Jun 15th, 2010 at 7:35am
Hello all,
another question on memory, demonstrating my total ignorance ... :-[ ... but a while back, I was in contact with Corsair Support but I didn't get him/her to understand my question.

For reference see Corsair ultra-high performance DDR3 Memory for AMD Phenom II Processors, the Recources tab.

For the Phenom II there are two 8 GB PC3-10666 kits (I have no intentions to overclock or fiddle with any other setting):

CMX8GX3M4B1333C9 which has been tested at SPD speed (1333 MHz) and SPD latency (9-9-9-24) at 1.5 V. This is the kit that I'd like to have but it's not readily available in "my shop".

Available in "my shop" is CMD8GX3M4A1333C7 which has been tested at SPD speed (1333 MHz) but latency 7-7-7-20 at 1.65 V. This memory profile is marked BEMP (Black Edition Memory Profile). The processor I have decided on is not a Black Edition.

Finally, the question: Will the motherboard GA-870A-UD3 default to SPD settings (1333 MHz + 9-9-9-24 at 1.5 V) for the CMD8GX3M4A1333C7 if the processor is not a Black Edition?

Title: Re: Corsair Memory with BEMP
Post by MrMagoo on Jun 28th, 2010 at 1:54am
If I understand the memory timings correctly, they are a measure of latency, not something that has to be set or detected.  Since they are both 1333 MHz, my understanding is that they will both be compatible with both processors.  The 7-7-7-20 memory should perform better with all processors since it has lower latency.

Title: Re: Corsair Memory with BEMP
Post by Christer on Jun 28th, 2010 at 1:06pm
MrMagoo,
in the meantime I've done some research and I have a different understanding. Motherboards default to JEDEC specifications and with DDR3 memory controllers and 1333 MHz the timings are 9-9-9-24. In addition to that, there are other settings that conform to JEDEC.

AMD has BEMP (Black Edition Memory Profile) and for the CMD8GX3M4A1333C7, the timings are 7-7-7-20 and the DDR3 controller should "read" the module and the BEMP specifications and automatically set those timings. Now, if the processor is not a Black Edition, I'm (almost) convinced that the controller will default to 9-9-9-24.

Title: Re: Corsair Memory with BEMP
Post by MrMagoo on Jun 29th, 2010 at 2:43pm
Interesting.  Perhaps a motherboard with advanced enough BIOS would allow you to set the timings for the controller.

Title: Re: Corsair Memory with BEMP
Post by Christer on Jun 29th, 2010 at 4:01pm
This is bordering on overclocking and I'm not into that but my understanding is:

The JEDEC voltage is 1.5 V but running the modules at 7-7-7-20 requires 1.65 V.

If the modules were e.g. 1600 MHz, that would require overclocking the processor.

There are "tons" of settings for the memory controller but that's not enough. You may have to fiddle with the settings for the processor as well.

Title: Re: Corsair Memory with BEMP
Post by MrMagoo on Jun 30th, 2010 at 3:59pm
Wow.  Interesting. 

I overclocked my processor back in the day just to learn how to do it.  It didn't get me much of a performance boost and the added cooling it necessitated made my computer louder.  These days, I tend to obsess over making my computer silent more than getting another 1% performance out of it. 

I always chuckle over these guys who use phase-change cooling (and all the necessary refrigerant and rubber seals and $1000+) all to get an extra 20% performance out of their computer.  Then, 4 months later the new line of processors come out and its just as fast or faster than their overclocked one.

Memory is an important bottle-neck, so I'd be interested in seeing what difference something like this would make in bench-marks.  That said, I'm usually much more impressed with the boost I get from an upgraded HD, and there aren't too many ways to overclock those.

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