Cpu to Dram ratio? confused!

#1

Can someone please explian which is better?

A cpu to ram ratio of 1:1 or not?

My M/B (Abit AB9 Pro Wifi) allows various settings for the cpu to ram
ratio, from 1:1 to 2:3 to 1:2 to 1:3 to 3:4 to 4:5 and I have no idea
which I should be using?

The stock setting was using 2:3 but I assuem that if you can gte the ram
and cpu rnning at the same speed (1:1) then this will give bset results,
is that correct?

Thanx for any info you can pass on. I have searched for info on this on
the net and just ended up confusing myself as sites seem to contradict
themselves (and / or other sites)!

#2

So what you are saying is that its ok to have the memory speed faster
than the FSB, therefore a ratio of 1:1 is not necessary.

So, if say my FSB is at 300 and I can get the memory to run faster than
this say a ratio of 1:2 this would equal mem speed of 600 (DDR2 speed of
1200)

Or likewsie if the FSb is 300 and I use a ration of 2:3 then the mem
speed would be 450 (DDR2 speed of 900)

etc, etc

Is that correct?

My memory is 2 x Gb of Crucial Ballistix DDR2 (PC2-6400C4 - 800MHz) dual
channel kit (running in dual channel mode)

And so far I have had it running ok at DRam clock 525 (DDR2 1050) using
a 2:3 ratio with the cpu (cpu FSB was set to 350) but I'm a bit confused
about which memory figure is the theoretical 800MHz max, is it the DRam
speed of the DDR2 speed?

Thanx

Quote:

The highest memory speed gives the best performance, even if the timings
must be relaxed. Depending on your BIOS settings, that would be unlinking
the CPU Clock and Memory Clock, then setting the Memory Bus or Memory Bus to
the highest your DDR2 modules can sustain.

#3

Phil Weldon wrote:

Quote:

The highest memory speed gives the best performance, even if the
timings must be relaxed. Depending on your BIOS settings, that would
be unlinking the CPU Clock and Memory Clock, then setting the Memory
Bus or Memory Bus to the highest your DDR2 modules can sustain.

See my post
E4300 overclocking with EVGA 680i motherboard on May 14, 2007
for SiSoft Sandra memory benchmark comparisons for DDR2 PC8500 memory
at 300 MHz Memory Clock (Memory Bus 600 MHz) and at 600 MHz Memory
Clock (Memory Bus 1200 MHz).

For my E4300 / EVGA 680i system this is a 1:2 CPU Clock : Memory
Clock ratio.

I have a different result, on my P5N-E SLI, also paired with an E4300.

I'm now running my FSB @1350 'MHz', memory in 'sync', so running at 675
'MHz'. At CAS 3-3-3-9-1T I'm getting 6850 MB/s bandwidth in Sandra. I
couldnt get this high numbers at 800 MHz, CAS 4-4-4-13-1T.

An added bonus of the low CAS numbers is, of course, a lower latency...

--
Met vriendelijke groeten, Thomas van der Horst

#4

Thanx for the explanation Phil...

Quote:

This topic has been the source of much confusion, and was discussed in this
newsgroup about six weeks ago.

Confused? you bet!, but learning more each day thanx to guys like you...

Quote:

If your Memory Clock is set to 525 MHz then your memory is running at
DDR2-1050, and is overclocked; 525 MHz is higher than 1/2 of DDR2-800.

I think I get the general idea now....I think!

8-)

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Cpu to Dram ratio? confused!

Hardware Overclocking Discussions about overclocking (alt.comp.hardware.overclocking)

Cpu to Dram ratio? confused! - 05-16-2007 , 05:20 PM

Re: Cpu to Dram ratio? confused! - 05-17-2007 , 02:58 PM

Re: Cpu to Dram ratio? confused! - 05-18-2007 , 03:08 AM

Re: Cpu to Dram ratio? confused! - 05-21-2007 , 04:40 PM