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Can someone help me with calculating speeds and frequencies?

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grishenko45

Member
Joined
Dec 2, 2008
hi guys,

for ages ive wanted to know the formula for the following;

finding out ram freq from the fsb and fsb ratio setting

finding out GPU mem bandwidth from only knowing the freq

if you know this would help - thanks

i found out this one - for ram bandwidth - i think its - ram speed*8/1000 : 1066*8 = 8528 / 1000 - 8.5Gbps

it works for DDR2 and DDR3 - but i cant seem to find out how to calculate GPU mem bandwidth!
 

TaCoSwInDeZ

Member
Joined
Nov 7, 2008
Location
Huntsville, Al
The actual ram frequency is pretty easy. It goes like this, you have your baseclock which we will say like for my I5 750 is 133mhz. If I have DDR3 1333 running at that frequency then I have a frequency ratio of 2:10 or a frequency multiplier of 5 giving 665 operating mhz. Now since its Double Data Rate (DDR) you take that 665 and you double that and it gives you 1330 (close enough to 1333) effective mhz on your ram. This is a crude representation but its basically like this;

Baseclock * ratio * 2(DDR) = Effective mhz.

As for the GPU mem bandwidth im not too sure. I believe your on the right track though, some googling would help you alot there.