I have some questions about choosing RAM for Sandy Bridge (i5 2500 or 2500K).
If the supported memory specification is 1066 or 1333 Mhz, what does that mean? I read that the P67 chipset supports memory up to 2133 Mhz, so I'm wondering how that whole thing works. Do you have to overclock some kind of part or bus to use memory at a higher frequency than 1333 Mhz?
I'm not sure whether I should get 1600 Mhz or 1333 Mhz memory for Sandy Bridge (as the difference in price is very little). I don't have a specific motherboard I'm looking at getting yet, but I'm really curious as to what the supported memory speed really means for the processor and how it can be different for the motherboard and what that means to the person using it.
If you can get 1600MHz RAM without paying more than $5-$10 more than do it, but if you have to get 1333MHz RAM its nothing to worry about since there's not a huge difference between the two.
Sandy Bridge's spec memory speed is 1333MHz, which means that's max speed you'll get with JDEC settings. 1600Mhz speeds will likely require the use of an XMP profile. On previous platforms XMP profiles often required increased BCLKs, but on Sandy Bridge the XMP profile probably just increases the BCLK : RAM ratio to acheive 1600MHz. So probably no overclocking platform components to use XMP on SB.
Edit: It appears that it is the K-edition processors that support unlocked memory ratios allowing for speeds up to 2133MHz. As far has how this affects XMP profiles and 1600MHz RAM I'm not sure.
I think even the non-K edition processors have unlocked memory ratios. I'm not sure how JEDEC and Intel's XMP all work. I know that XMP is for using memory above JEDEC standards (such as DDR3-1600 with CL 7 which is outside standards), but well, I'm not very knowledgeable about any of this. If you increase the memory ratio, is that making something work harder (like overlocking a CPU via clock ratio does), that they'd call it "not supported?"
I'd have thought the memory ratio would automatically set itself whether you're using 1066 or 1333 DDR3 and that an unlocked memory ratio which lets you go up to 2133 is just the same thing and hence would make 2133 DDR3 "supported."
What does supported versus unsupported mean to Joe User? It means that your new DDR3-2133 RAM kit will default to DDR3-1333 speeds. You will have to go into the EFI/BIOS and either enable XMP or manually change the speed and timings.
Sometimes, this does require that you also bump the DRAM and VCCIO/VCCSA voltages up a notch or two to make things stable.
No, it will not limit your performance when overclocked. Performance will improve a few percentage points with faster RAM, and DDR3-1600 seems to be the "sweet spot" for Sandy Bridge CPUs.
It will default to 1333MHz most likely. You just go into the BIOS and specify 1600 (or 16x memory multiplier) and it will work at that speed.
There are certain server boards out there now that are quad channel. However, most consumer boards are dual or triple channel. That means when you install RAM, to get the most performance you have to install the RAM in pairs for dual channel and threes for triple channel.
You just paid extra for G.Skill to test those memory sticks so they would work together all nice and cozy. Would have been cheaper to get two dual-channel kits, but it's no big deal. I bought an 8GB kit and a 4GB kit for my new Sandy Bridge system from NewEgg because of their 15% off memory sale. All the parts should arrive Friday.
It's hard to adjust to the pricing considering my last build had 6gb of ram that cost the same as this 16gb kit and was nearly the cheapest 6gb kit at the time. Even if I could get it cheaper it still feels like a bargain, haha!