Corsair Dominator DDR3 1800MHz Intel XMP Memory Review
In its most basic form, Intel Extreme Memory Profiles (XMP) are a way for both Intel and enthusiast memory providers to allow easy and automatic memory bus overclocking. As an extension of JEDEC SPD settings, an XMP profile exists on the module and when paired with a compatible Intel Extreme series chipset, allows for overclocking the modules over standard JEDEC settings with a single selection in the BIOS.
Here we can see just such an option with our Corsair Dominator XMP modules and our Asus P5E3 Deluxe motherboard using the Intel X38 chipset. While the process will vary from board vendor to vendor, for our motherboard selecting XMP under the "Overclock Tuner" is the first step to unlocking these profiles. We are then presented with a couple of options for which XMP profile to use.
The description on the right hand side helps to explain what you are actually picking: either a standard OC profile selected by Intel and placed in the SPD or the more aggressive profile installed and tested by the memory vendor. For almost all cases, to get the most out of your XMP memory, selecting the second option here will offer better performance as no one knows the memory sticks better than the memory vendor themselves. Also, when selecting an XMP profile, you get a note that other OC settings like the CPU multiplier will not be available as those are manually adjusted by the XMP data itself.
I really would like to see a much more descriptive answer to what these profiles specifically do while in the BIOS -- it would be nice to see the actually clock speed and timing changes that are going to occur when we simply select profile 1 or 2. Right now, it's mostly a "shut eyes and point" tactic to getting the user information about what they are doing to their PC.
Our testing was done with the Asus P5E3 Deluxe motherboard using the X38 chipset and the uber-faster Intel Core 2 Extreme QX9770 processor
. The CPU, that isn't actually out yet, runs at a 1600 MHz front-side bus with a clock speed of 3.20 GHz making it the fastest desktop processor to date and hopefully a good way to test our Corsair memory.
In the above CPU-Z shot, which is what the system booted at when we selected XMP profile #2, indeed shows the system running at an overclocked speed.
Instead of the 3.20 GHz core, we are running at 3.60 GHz thanks to a 50 MHz bump in our bus speed. The result is a front-side bus of 1800 MHz.
Looking at the memory tab in CPU-Z we see that indeed now, our DDR3 memory is running at 1800 MHz! My only concern is that the timings of 7-7-7-20 as promised on the Corsair labels weren't automatically enabled and I was not able to manually set them with XMP profiles enabled.
Let's see how this changes our performance!