Jumped the gun

[russell]

I bought a stick of Ultra 256MB DDR 400MHZ PC3200 to go with a stick of stock PC2700 DDR 333MHZ PC2700 for a total of 512MB RAM.
I wonder how much noticeable improvement I would see if I also upgraded the 2700 to match the 3200.
Now the Timings read
Freq. 133.3
FSBRAM 3:4
CAS# Latency 2.0 clocks
RAS# to CAS# Delay 3 clocks
RAS# to Precharge# 3 clocks
Cycle time [tras] 6 clocks

It's running with
Intel celeron 2.6 GHZ
FSB 100MHZ x26
intel i845 gv chipset
MS6577 MOBO

!#&$ <font color=blue> </font color=blue>---<font color=red><i><b>It's not heavy,...it's my computer</font color=red></i></b>

 

[Crashman]

I don't think your board supports a rate higher than 3:4, so I don't see how you're going to get the RAM frequency up unless you overclock the FSB.

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[russell]

Hi Crashman..how ya doing?
Thanks for helping.
Then at least I wont have to spend more money right now.
What exactly does a rate of "3:4" refer to?
The <A HREF="http://h10025.www1.hp.com/ewfrf/wc/genericDocument?docname=c00063244&dlc=en&lc=en&cc=us#N10012" target="_new">MOTHERBOARD SPECS</A> do limit the ram supported to 333MHZ and PC2700 but the <A HREF="http://www.msnusers.com/Russellchamberspage/Documents/cpuz.htm" target="_new">CPU-Z report</A> says that I'm only at 133.3MHZ, what is it that I'm not understanding here?
As far as OCing the FSB I dont think that this board will let me do that.


!#&$ <font color=blue> </font color=blue>---<font color=red><i><b>It's not heavy,...it's my computer</font color=red></i></b>

 

[Crashman]

OK, I've repeated this to around 200 people so far, so pardon my lack of enthusiasm:

Your CPU has a Quad Data Rate bus. That means with the bus having a clock frequency of 100MHz, it has a data rate of 400MHz, because data is transfered 4 times per clock cycle.

Your RAM has a Double Data Rate bus. That means with the bus having a clock rate of 133MHz, the RAM data rate is 266MHz, because data is transfered 2 times per clock cycle.

The reason we have "Dual Channel" chipsets now is because quad data rate has twice the bandwidth of double data rate, and dual channel mode makes the bus twice as wide.

Now, without dual channel your memory bus has much less bandwidth than the CPU bus. So they allowed modes on your single-channel chipset to make the memory faster than the CPU bus.

Since you don't have dual channel, the best data rate you could have your memory run at is 400MHz, to match the CPU data rate of 400MHz: But that would force you to run your RAM at twice the clock speed (200MHz) of the CPU (100MHz).

So the ratio is the clock rate ratio of the CPU bus to the RAM bus. The "split" happens in the chipset at the memory controller. A ratio of FSB:RAM of 3:4 gives you 100:133 MHz. That's what you're running now. Another ratio was included for 133MHz bus processors (P4's with the so-called 533 bus) to run the RAM at 166MHz (DDR333), that ratio is 133:166 based on the 4:5 ratio.

I believe those are the only two "RAM faster than CPU" ratios available on your chipset. Some BIOS will refer to the ratio, others will have you set a base speed for the RAM, which actually sets the ratio.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>

 

[russell]

Thanks that helped clear things up. Sorry you had to repeat things again. I have been reading the posts here trying to increase my understanding and have found some web pages that help too but it's nice to be able to get answers to questions that you have.
When you said that

The reason we have "Dual Channel" chipsets now is because quad data rate has twice the bandwidth of double data rate, and dual channel mode makes the bus twice as wide.

Now, without dual channel your memory bus has much less bandwidth than the CPU bus. So they allowed modes on your single-channel chipset to make the memory faster than the CPU bus.

Since you don't have dual channel, the best data rate you could have your memory run at is 400MHz, to match the CPU data rate of 400MHz: But that would force you to run your RAM at twice the clock speed (200MHz) of the CPU (100MHz).

I did some research and <A HREF="http://www.kingston.com/newtech/MKF_520DDRwhitepaper.pdf" target="_new">this web page </A> helped a lot. Maybe others will like to read it too.

Anyway I guess that with the mobo I have I'm maxed out on preformance unless I increase memory to a Gig.

Thanks again crashman

!#&$ <font color=blue> </font color=blue>---<font color=red><i><b>It's not heavy,...it's my computer</font color=red></i></b>