# DRAM Frequency/maximizing bandwidth



## cly (Mar 1, 2010)

I am running A-Data 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3-12800).  However in CPU-Z it says the DRAM Frequency is 669.7 MHz so it says the max bandwidth is PC3-10700. Which i understand is (669 MHz * 2) * 8 = 10700.  But this is 1600, so my question is how do I get it running at 1600.  CPU-z says my FSBRAM is 3:10 which makes sense why my DRAM freq is 669.  MY FSB is 200MHz so (10/3)*200 = 669.  Should I change my FSBRAM to 1:4?  Is this possible in the bios? or is there a better way? Also, on NewEgg it says this ram should be run at 1.65v-1.85v but CPU-z says it is at 1.5v. Thoughts? Thanks

AMD Phenom X2 555be
Gigabyte GA-MA790XT-UD4P


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## slyfox2151 (Mar 1, 2010)

are you not able to change your ram speed by itself to 1600? or even 1300 without upping the fsb?

if not then upping the fsb will also incress your CPU frequency witch is good but it may become unstable if you incress it too high... you should read up on overclocking before doing so.

you could also raise the FSB to incress the ram speed but at the same time, lower your CPU multiplyer to keep it around its current frequency.


also wile your in there, Manualy set the Ram Voltage and timings to what they should be. set the ram to 1.7v and see if its stable at 1600mhz, if not go higher untill u gain stability or reach 1.88v. ( read up on your ram to see what timings it requiers.)


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## copenhagen69 (Mar 1, 2010)

slyfox2151 said:


> are you not able to change your ram speed by itself to 1600? or even 1300 without upping the fsb?
> 
> if not then upping the fsb will also incress your CPU frequency witch is good but it may become unstable if you incress it too high... you should read up on overclocking before doing so.
> 
> ...



+1
raise your FSB but watch your CPU-freq and you should be good to go with the rated mem speed


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## cly (Mar 1, 2010)

My bios is set to auto so the memory clock is set to x 6.666 = 1333.  Why wouldn't it default to x8 = 1600.  Is there a risk to changing it?


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## copenhagen69 (Mar 1, 2010)

it loads safe defaults ... then you change them to the rated specs if need be.


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## cly (Mar 1, 2010)

I changed it to x8 so my DRAM frequency is 803 MHz.  But my timing went from 9-9-9-24 to 11-11-11-29.  Should I change this? Also, the max bandwidth still says PC3-10700 (667 MHz) on the SPD tab of CPU-Z.


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## copenhagen69 (Mar 1, 2010)

ya if you leave your timings on auto the mobo will change them around if you mess with things ...

set the ram at manu. specs ... or at least try to


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## cly (Mar 1, 2010)

I've made some changes.  Is there a good way to check to see if the settings are stable?


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## copenhagen69 (Mar 1, 2010)

prime 95 and linx are pretty solid to test


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## cly (Mar 1, 2010)

Which site would you download prime95 from


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## copenhagen69 (Mar 1, 2010)

could try EOCF http://files.extremeoverclocking.com/file.php?f=103

sorry if i missed it on TPU :/


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