Santa Rosa - upgrade to ddr2 800

Who plans on getting a Santa Rosa notebook now and upgrading the memory to DDR2 800? I want the optimal setup so I'm thinking of a Lenovo T61 w/1GB DDR2 667 and upgrading it to 2GB DDR2 800 from here.
That memory should be compatible with the T61 and unlock the full potential of Santa Rosa's 800Mhz FSB, correct?

Thanks

 

The Northbridge (a.k.a. the 965PM does not support DDR2-800) we [some forum members] are still trying to figure out how Zepto is supposed to put DDR2-800 in their Santa Rosa laptops.Unless they are overclocking/tweaking something.

 

doesnt support? that's kinda stupid of them to implement a new platform with such a ridiculous limitation. maybe zepto are underclocking the RAM but making it look like theyre giving you this feature. or perhaps there is a future tweak/bios that will support DDR2-800

actually no it isnt stupid, its crafty. next time theyll introduce a chipset that will support that RAM and dupe the public into thinking such things make a huge difference. perhaps introduce it when AMD bring theirs in?

 

The 667 MHz RAM isn't a limitation, if you realize that the data is transferred at twice the RAM's speed, in the DDR structure. Or closer to 1300 MHz, for the DDR2-667. While the FSB in the santa rosa still is 800 MHz. It's quite far from saturating the memory bandwidth yet.. In any case, Intel has said it'll use DDR3-800MHz, not DDR2, when it implements it.

 

You are wrong on this one.
The DDR2-667 is clocked at 333MHZ but due to the Double Data Rate it's effective rate is 667MHz.The same is for DDR2-800 (it's clocked at 400MHz).
And about the DDR3, we will not be seeing that until the Motevina platform.

 

I agree with the Montevina implementation of DDR3.. I may be wrong, but it was my impression that DDR2-667 operated on 1:1 timings.

 

Yes, at the effective rates, the FSB:RAM ratio is one (note : FSB is clocked @ 166MHz but it has Double Rate and Dual Lane so 166x4 = 667)

 

DDR2-667 should have no problem feeding the CPU with enough bandwidth so it's not really a problem. If we could get lower memory timings on the 667MHz memory for notebooks it would probably give more of a boost than hypothetically going to DDR2-800.

 

Will Santa Rosa finally make DDR2-667MHz a better option than DDR2-533MHz? I know that there was little difference between the 2 performance-wise with the old Napa platform.

 

The D900C has a P965 desktop processor, perhaps the 200 pin DDR2 800 is for that?

 

Good point Mujtaba! How did they got 800 MHz DDR2 working on the Zepto? I read everywhere that the maximum speed was 667 MHz.

I hope you have an explanation about this fact, I find it strange.

 

This is starting to piss me off. The more I look at this launch, I'm forced to ask what's the point? If the northbridge doesn't support 800MHz RAM, then what good is having an 800MHz FSB? Everything goes through the northbridge, so this makes no sense. Seems like all marketing to me.

 

As one of the members pointed out, the base clock of the FSB is used for the CPU.For NAPA laptops, the clock is 166Mhz [and as I said Double Data Rate + Dual Lanes = 4x = 667MHz] .It gets multiplied by 11 for 1.66 and 12 for 1.83.for Santa Rosa.The raised clock will help the CPU reach higher clocks.

 

I see, that does make sense. However I don't think that's a big enough change to be touting 800MHz!!! everywhere when it doesn't actually talk to anything other than itself at that rate. At least it will save me on buying the PC2-6400 RAM I was looking at.

 

Actually i think it was the power factor that prevented ddr2 800 coming to santa rosa..
So there are chances that a tight timed ddr2 400 can beat ddr-533 (!?)

 

DDR2 is "double data rate 2," where as DDR is "double data rate," which means effectively that DDR2 is "double double data rate," or "quadruple data rate." So, even though DDR2 runs slower, it can still handle more bandwidth than the DDR.

 

my bad i meant ddr2 400 and ddr2 533..

 

DDR2 800 is definitely faster than DDR2 667. It is different from 533 to 667 where later is slow down by its latency issue. DDR2 800 has almost identical latency as 667.
DDR2-800 is actually favor to AMD rather than Intel. Intel always use 166M clock base. It good for 533, 667. But AMD's 200M clock base exactly fit the DDR2-800. Because Intel memory controller is outside of CPU, so it won't get CPU actual running clock. It has to use it's own multiplier start from 166/133. Somehow Intel don't make the FSB multiplier higher than 4(133x2=266 DDR2-533). So, 800 require 133x3=399, that's very odd isn't it?

I think Intel is envision the DDRx-1333 or DDRx-1066. Power is not a problem at Intel.

 

Very interesting replies, but too complicated for me. I would actually want to see a few screenshots of CPUz that show at what speed the DDR2 on that Zepto ran.

I was hoping for 800 MHz DDR2 to work.