Need solution for 800Mhz Ram With Santa Rosa [PIC]

[raid-5]

Every ppl got T61 want the CPU and chipset to take the advantage of 800 MHz ram which is available at newegg,
and I'm pretty sure lots of you guys have already ordered yours.


Two difficulties are in front of us
1. Does 965 really support 800 MHz ram
2. If 800 MHz ram is official supported, will they really boost the speed?


First, according to the documents that I can find(Intel's PDF at page 39)
http://www.intel.com/design/mobile/datashts/316273.htm

"At bus clock speeds of 133-MHz, 166-MHz and 200-MHz,
address Signals run at 266 MT/s, 333 MT/s and 400MT/s,
which amount to a maximum address queue rate of 64, 83 and 100 Mega addresses/seconds, respectively.
Data signals are quad pumped and an entire 64-B cache line can be transferred in two bus clocks.
At 133-MHz, 166-MHz and 200-MHz bus clock,
data signals run at 533-MHz, 667-MT/s and 800-MT/s
for a maximum bandwidth of 4.3-GB/s, 5.3-GB/s and 6.4-GB/ seconds, respectively."

So, I still believe 965 chipset can take the advantage of the 800 MHz ram

According to this pic I find on the web 667 ram with 7300 T61 single channel


The front bus: Ram is at 3:5 which is 200:332.5

If FSB:Ram lock at this ratio, we have to find some hardcore guy doing a bios mod


Second. If 800 MHz ram is supported

I heard that 965 is talking to ram at 64bit the band width is too small,
so even the signal ram and dual channel won't have a big difference.
If this is the case,,,,, 667 MHz dual channel will be an over kill,
why 800 MHz then.... some one can confirm this or correct me on this plz?
I really hope this is not the truth

[XIII]

You are interpreting it all wrong.
Dual channel does not work like that. It is similar to the misconception that dual core is equivalent to a processor with twice the clock speed of 1 core. Just imagine you have same amount of water with two pipes to transfer instead of one. The speed of the fluid inside the pipes will be same because they have the same diameters but in the same time you can transfer roughly twice the water if you are using one pipe.

[raid-5]

well,

I know what you mean.

The ram is runing at 333 mhz for sure,

but the North bridge is talking to then at 667 mhz if it's dual channel.

that's why we say it's 667 mhz dual channel ram.

pretty much like raid-0

if the hard drive's speed is 100m/s,

two drives raid-0 will leads the raid card talking to the south bridge at around 200 m/s

[XIII]

No, even if you run in single channel mode, it is still 667MHz. Because the RAM speed display is half-duplex, it resembles how the FSB is quad-pumped. If the FSB is 667MHz, the actual speed is 166Mhz.

[raid-5]

yaya, my bad, I siad it wrong

the ram is 166 for 667.

I've edited the first post to correct it.

[patch]

Although this is a little bit less technical, according to intel's overview of centrino pro (seen here), the Centrino pro only supports ram up to 667 mhz despite the front side bus being 800 mhz on all models.

[barrywohl]

Will 800 MHz FSB ram give a bit more speed on some applications or not?

[shuffle2]

http://en.wikipedia.org/wiki/Double_data_rate
"...a computer bus operating with double data rate transfers data on both the rising and falling edges of the clock signal, effectively nearly doubling the data transmission rate without having to deal with the additional problems of timing skew that increasing the number of data lines would introduce."

http://en.wikipedia.org/wiki/Dual-channel_architecture
"Dual-channel architecture DDR/DDR2 SDRAM describes a motherboard technology that effectively doubles data through output from RAM to the memory controller. Dual channel-enabled memory controllers utilize two 64-bit data channels, resulting in a total bandwidth of 128-bits, to move data from RAM to the CPU."

important to know what you're talking about

edit: might as well throw in http://en.wikipedia.org/wiki/Front_side_bus too

[XIII]

That is why I said you guys get it all wrong. The display speed for the RAM is before being multiplied by two for double data rate not dual channel. Dual channel keeps the speed, just up the bandwidth because now you have two lanes for data transfer. DDR2-667MHz has speed before upped by Double Data Rate is 333Mhz, not 166Mhz.
Remove the 2nd stick to break the Dual Channel mode and you will see the RAM speed is still 667Mhz.

[Dead1nside]

Wow there's a lot of confusion except for the previous poster.

DDR RAM, means double-data-rate. This means for a given clockspeed say 400Mhz, that this is doubled as data is transmitted twice per clock, instead of just once.

Dual-Channel from what I understand has to do with the upping of bandwidth when the RAM is in two channels (see two, dual, see?)

[shuffle2]

Wow there's a lot of confusion except for the previous poster.

DDR RAM, means double-data-rate. This means for a given clockspeed say 400Mhz, that this is doubled as data is transmitted twice per clock, instead of just once.

Dual-Channel from what I understand has to do with the upping of bandwidth when the RAM is in two channels (see two, dual, see?)

uhhh yes, i think we just about convered this....