The importance of the fsb:dram ratio

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12 Jan 2013
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Hi OCUK,

I recently purchased and installed a RAM upgrade, the new kit is ddr3 2200 8gb dual channel corsair.

I found in cpu-z that I was getting a fsb:dram ration of 1:7 from install with asus' standard "mediumish" oc profile in the bios.

My question is how important is the fsb:dram ratio and should I be looking to be bringing that ratio to 1:1 or at least close to it? I think I saw a readout that said the ram was running at 1333mhz which is almost half of its intended speed. And cpu-z was reporting even lower.

I'm not a hardcore/extreme user looking to max oc speeds on everything, but at the same time im not a casual user that plugs it in and expects it to work. If im only getting a fraction of the capabilities out of my ram then i'd like to bring it up to its intended speed with the correct bios tweaking.

Any advice is appreciated.

ps. I'm running:
intel i5 3.3k at asus mobo oc to 4.2k very stable
asus p8p67 pro rev 3.1
 
You will need to double what CPU-Z shows.

If this is not running at the rated speed thn pop into the BIOS and enable the XMP profile or you will be able to manually configure the speed and voltage ect.

Oh, Hello and welcome to the forum :)
 
Hello,

Thankyou for your welcome and your advice.

I had a look around in the bios and I found the xmp profile and enabled it and it detected that it is 2133mhz RAM and found the right settings for it. But when I booted into it cpu-z now reports the ratio as 1:8. And if I ran any of the "tuner" applications, either from the bios or the asus tuner, it resets the xmp profile, but it does return to the 1:7 ratio and has returns faster cpu speeds than the xmp does.

What would my next step be in trying to correct the fsb:dram ratio ? I assume a manual overclock would be necessary to balace the cpu to the ram accurately. In previous manual overclocks the settings in the bios were fairly simple but I find the current version of asus bios I have very confusing.

edit:

I found this thread on some other forums where someone asked a similar question. Apparently the 1066 dram frequency that I am seeing in cpu-z is correct because the memory runs in dual channel so it shows half the "actual" speed. (dont really understand but I guess ill assume they are right)

In the thread starters screenshot his cpu-z is reading exactly the same as mine with 1066 1:8 9-11-10-27. Is this normal then? For the fsb:dram ratio to be off-whack even if they are running at correct speeds.
 
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Don't bother with tuner applications, they're not as good and stable as a proper manual overclock.

You don't really need to worry about the FSB:DRAM ratio either, it doesn't matter that much with Sandy/Ivybridge. Just reset everything, enable the XMP profile and change the CPU multiplier to 42/CPU speed to 4.2ghz and you'll be fine.
 
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