Sign in with
Sign up | Sign in
Your question

Ram/FSB to a 1:1 Ratio Questions

Last response: in Overclocking
Share
June 18, 2007 1:06:13 AM

Ok, I've been doing digging and digging to try and find some decent examples on how to overclock and why its so important to get a 1:1 FSB ratio with my ram. Yes yes, there are many posts on how to bring your FSB up to overclock your CPU but I don't see anything really detailing the pluses of keeping a 1:1 ratio and further more... how at least with my mobo.

Let me start with system Specs here.

Mobo:
eVGA 680i SLI (122-CK-NF68)

CPU:
Intel Pentium Core 2 Duo E6700

Memory:
4 x 1GB of DDR2 800Mhz Patriot Extreme LL (4-4-4-12) PC6400

VideoCard:
BFG 7950GT

---------------------------------------------------------------------------------

So, I've overclocked by Vidcard and I've overclocked my CPU... however I am hesitant to really put in some serious attempts at overclocking my ram. I've adjusted my voltage to 2.1v per the rams specifications. I've read up alot of reviews that say time and time again to get a 1:1 ratio for the ram to FSB. I've taken some pictures of my Bios options since they seem to differ from any of the other tutorials. I've read threw my owners manual of the mobo aswell and it doesn't give me much of an explanation for the the ratios or what "synced" mode is.

Here is my current settings which show an unlinked:


Here it is linked, set to a 1:1 ratio... notice its at 1300mhz:


And... here is the closest thing to what I want (Synced, which I'm assuming its "Syncing" with the actual FSB):



What I seem to get is that when I "link" with a ratio of 1:1 its getting quad pumped to 1300mhz, which... I'm not even going to attempt to run the ram at that speed. When I "Sync" it, the ram drops to 650mhz which seems to be a true 1:1 ratio since my actual FSB is 325.

So I want to run my Processor at about 3.4ghz, and my Ram as close to 800mhz as I can... So I just basically want a confirmation that I would be doing the right thing by dropping my core multiplier to 9, bringing up my FSB to 378mhz (1512FSB), having my Ram "Synced" so it would run at 756mhz actual speed, where I can then tighten down my timings.

Some assistance would be greatly appriciated.
a c 83 à CPUs
a b K Overclocking
June 21, 2007 6:14:07 AM

Is there a reason your shooting for 378MHz and not 400? If you set the base frequency to 400MHz, you can run your CPU at 3.6GHz, your ram at 800MHz (DDR) and your FSB at 1600MHz. 378MHz will give you 3402GHz, but I'm not sure why your worried about 3.4GHz. It seems a little silly to me to shoot for the lower number. As a side note, I'm not sure how low you can get the timings, or how well these four sticks will OC. Usually, the more sticks you have, the lower the OC. (at least with the AMD systems I'm used to.)

As for the benefits of 1:1, why not test it yourself? Before you do this overclock, why not try some 800MHz ram with "normal" timings, and some 650MHz ram with tighter ones. My guess, from all the reading I do, is that there will be little to no real difference. Synthetic memory benchmarks will probably claim the 800MHz to be faster, but most real world apps will show little to no improvement.
Related resources
June 21, 2007 7:00:29 AM

Well, the reason I've been trying to shoot for 3.4ghz for processor is because the CPU doesn't post.. I've ran it at 1.45v and pushed it to 3.4ghz and I had to flash my bios to get it to boot again.
a c 83 à CPUs
a b K Overclocking
June 21, 2007 7:13:56 AM

You had to flash your bios or reset it? I could see resetting it, flashing I don't understand.

If your CPU can't do 3.4GHz, try this. Set the base speed to 400MHz, and drop the CPU multiplyer down to 8. This should give you a 3.2GHz CPU, a 1600MHz FSB, and the 800MHz ram.
June 21, 2007 8:12:54 AM

I appriciate the info. I'm going to try that... (I've heard that pushing to 1.5v should help with the cpu). I do know some people running E6600 and below at 3.6ghz so i'm sure I just did something wrong (i'm a noob after all :( ) This weekend when I have the time to really sit down and try different settings then I will give it some shots. Come to think of it I did push the FSB up while trying to tighten down my memory timings so it probably wasn't even my CPU that caused the failure to post.
April 26, 2009 1:51:57 AM

4745454b said:
Is there a reason your shooting for 378MHz and not 400? If you set the base frequency to 400MHz, you can run your CPU at 3.6GHz, your ram at 800MHz (DDR) and your FSB at 1600MHz. 378MHz will give you 3402GHz, but I'm not sure why your worried about 3.4GHz. It seems a little silly to me to shoot for the lower number. As a side note, I'm not sure how low you can get the timings, or how well these four sticks will OC. Usually, the more sticks you have, the lower the OC. (at least with the AMD systems I'm used to.)

As for the benefits of 1:1, why not test it yourself? Before you do this overclock, why not try some 800MHz ram with "normal" timings, and some 650MHz ram with tighter ones. My guess, from all the reading I do, is that there will be little to no real difference. Synthetic memory benchmarks will probably claim the 800MHz to be faster, but most real world apps will show little to no improvement.



i read your post and i would like very much to ask you a question i have a kentsfield Q6600 core2 quad @ 2.4ghz rated fsb 1066, i have a MSI p6n sli motherboard, blue orb cpu cooler, 8gb ocz gold 800mhz DDR2 pc2-6400 4x2, EVGA GTX260 1260 AR, raidmax 630w modular psu,


im haveing problems with my gpu it gets like 89 0c and shuts off if you have any thoughts on that that would be grate. ive also been reading on the 1:1 ratio on the fsb dram mine is runing @ 2:3 how do i change this in the bios to
1:1 thanks i have the cpuz so i can give you any info you need
June 13, 2009 9:54:23 AM

To the threadstarter about 1:1 on this board.

I've been crapping around with this myself, as the 'sync mode' or "1:1" mode are borked. It's pretty stupid that the board wants your ram to run at a fictive bus speed (x4) while your memory is only a fictive x2 .
All this 'quadruple aw3some pumped' crap is lame.

The bus is running at say 400 mhz. Not 4 times faster.
Granted, 1600 sounds way cooler but the FRWEAKING BUS IS RUNNING AT 400 !
I personally do not care how much more information there is passing through the bus compared to 10 years ago, the bus is still running at that speed.
/rant at manufacturers :) 

Anyway, you need to pick 'unlinked' , then pick an FSB that is dividable by 2.
Then set your memory speed at half the bus speed manually.

Meaning that you punch in the numbers in bios.

Now you will have a true 1:1 ratio .

One more thing though .. I seriously doubt that there will be much of a performance difference between 1:1 or say 15:16 , but it seems to be a lot more stable though.

The only noticable performance increase i have seen with is aquamark3 benchmark, which is old and more of a cpu benchmark these days, which also happens to be very finicky about memory timings as well.

And then still, a 253k or 245k score is still a pretty close result performance wise.

Read this about mem timings vs mem speed : http://www.tomshardware.com/reviews/ram-speed-tests,180...

September 24, 2009 1:29:47 AM

1:1 increased my score in windows 7 from 7.3 to 7.4 for CPU and RAM

Originally had fsb 400 and ram 1066 (causing BSOD) after changing to fsb 400 and ram 800 (stable now) score went up to 7.4.

Processor Q9550 (default FSB 333 x 8.5 multiplier)
Corsair Dominator (1066) 4 x 2GB = 8GB
a b à CPUs
a b K Overclocking
September 24, 2009 10:09:19 AM

Ah, but wait... there's more! :pt1cable:  Let's consider some of the additional variables involved in the memory big picture: :o 

A ratio of 1:1 provides the best level of stability, since the memory controller, which is an integral part of the northbridge chipset for Intel Core 2 processors, does not need to translate data flow across the FSB between the memory modules and the processor(s). Also, since memory and processor FSB clocks are synchronous at 1:1, (400:400 or DDR 800), there is no additional latency introduced.

If a minimal ratio of 4:5 (400:500 or DDR 1000) is used, then the resulting increase in memory frequency is effectivey cancelled out by the latency introduced in translation across the FSB between memory and processor clocks, and no increase in memory performance can be noticably detected in benchmarks. Also, asynchronous or mismatched clocks create an element of potential instability within the memory controller, so depending on the chipset, an increase in northbridge and memory voltage is required for stability, which results in more heat, and less FSB overclock ceiling.

If a more aggressive ratio of 2:3 (400:600 or DDR 1200) is used, then the increase in memory frequency can marginally overcome the latency introduced in translation across the FSB between memory and processor clocks, resulting in a marginal increase in memory performance, which typically yields an increase in memory benchmarks of 2 to 3%, and is relatively negligible in terms of overall system performance.

In the case of DDR3, where a ratio of 1:2 (400:800 or DDR 1600) or 2:5 (400:1000 or DDR 2000) is used, even with the tightest timings, an increase in memory benchmarks of only 3 to 4% is yielded over DDR2 800, which once again, is relatively negligible in terms of overall system performance. It's also noteworthy to consider that DDR2 memory timings of 4-4-4-12 compared to 5-5-5-15, will yield an increase in memory benchmarks of less than 2%. However, for those of us who have the need for speed, we'll take whatever we can tweak.

Additionally, at equal specifications, 4 memory modules offer less FSB overclock ceiling than 2 modules, since more northbridge and memory voltage is required to maintain stability, and 4 slots require twice the current of 2 slots, again resulting in more heat, which typically is pulled into the CPU cooler, where it can increase processor temperatures by a few unwanted degrees.

I hope this helps to provides a greater degree of perspective (no pun intended). :D 

Comp :sol: 
a b à CPUs
a b K Overclocking
September 24, 2009 10:37:49 AM

jackcrackerman said:
What I seem to get is that when I "link" with a ratio of 1:1 its getting quad pumped to 1300mhz, which... I'm not even going to attempt to run the ram at that speed.


Your board and BIOS are showing the effective clocks at FSB - Memory Ratio. Setting this to "1:1" is just that, 1300:1300. This is not a frequency ratio, but a clock ratio. The setting name above it gives it away, it's called FSB - Memory Clock Mode, not FSB - Memory Frequency Mode.

On your board you require the Sync Mode setting to achieve what most refer to as 1:1 frequency. The bus frequency is 325MHz, the ram frequency is 325MHz and is reported at it's clock speed (DDR2) of double that, 650MHz effective.

As already mentioned, the gains in moving away from Sync Mode to other ratios are 1-4%. I read that as being not worth the effort. Let them hang out to 6-6-6-18 and the difference will not be noticed, either.

!