It appears K10 will be able to utilize up to DDR2-1066 RAM. What I am slightly concerned about is what this means for current AM2 owners looking to upgrade to K10, most of whom own DDR2-800 max. It has been mentioned many times already that AM2 K8 is very sensitive to memory speeds, eg. using DDR2-667 results in 5 - 10% lower performance than DDR2-800.
Now what I'm a bit worried about is if K10 shows similar memory speed scaling, this could result in most current AM2 users having a difficult choice to make: Make do with ~10% lower performance and stick with their existing DDR2-800, or upgrade to DDR2-1066 to get maximum performance.
Of course there is always the option of overclocking their existing DDR2-800, but to reach DDR2-1066 means a 33% overclock, and not that many DDR2-800 sticks can do such speeds, and even the ones that do will probably require relaxed timings, so it sort of defeats the purpose of overclocking the RAM in the first place.
Hopefully the L3 cache on K10 will results in a lower reliance on memory speeds to deliver good performance. If DDR2-800 is 'only' ~5% slower than DDR2-1066 I'll take that as a good result.
PS. TheINQ makes a goof as usual , they mention DDR2-1066 as in '1:1' sync with Penryn FSB. This is clearly incorrect, as Penryn will sport a 1333FSB, which means DDR2-667 would be 1:1, as the FSB is quad pumped, and the RAM double pumped.
I don't think the extra bandwidth will do much except in some specific applications. Dual-channel DDR2-800 has been proved not the bottleneck of Core 2 Quad processors. :wink:
I'm aware C2D/C2Q doesn't show much scaling with increased memory speeds, but I'm more interested in the impact this has on K10, hence the thread title. I merely mentioned Penryn FSB/RAM sync because it's just another in the line of elementary mistakes by TheINQ, and I can't let such misinformation go without saying something.
If, as it appears, K10 has been designed with DDR2-1066 in mind, then current AM2 users with 'only' DDR2-800 may suffer a small to moderate performance hit, depending on how effective the L3 cache is at alleviating the 'reliance' on fast memory to achieve good performance.
There is also the question of whether AM2 can run DDR2-1066 'unofficially', I'm assuming it doesn't have a problem doing so?
I think the dual IMC is the solution to the sensitivity.
Dual IMC?! That's news to me... care to elaborate?
I'm talking about current AM2 users btw...
The integrated memory controller (IMC) will get a few new features in the K10 core. When utilizing multiple memory modules, along with proper BIOS implementation and mainboard routing, the IMC can access memory in 64-bit channels (72-bit if you use ECC). This way it is possible to read and write data simultaneously, or improve efficiency for irregular access patterns which increasingly occur in a quad-core environment. This feature is available on AM2+ and F+ boards; on "old“ socket AM2 and F boards the usual 128-bit dual-channel mode is available.
Is this what you mean by 'dual IMC'? If so, this feature is still only available on AM2+.