PC Peripherals DDR2 RAM, 667Mhz or 800Mhz ?

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HoliC

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Im planning to buy 4gb 800mhz ram.

But i just found out on the net tht there are two versions of my processor

Amd Athlon 64 x2 dual core 5600+

Mine is 2900Mhz 65w Brisbane core.

and the other one is 2800mhz windsor core 89w.

So will a 800mhz ram work fully wid this processor, bcoz i heard procseesors with speeds of 2.1 ,2.3 , 2.5, 2.9 Ghz support only upto 667 mhz of ram.

Please help me out.
 
it more depends on your motherboard and not your processor , please post which motherboard u would use.......even if your board supports only 667 and u use the 800 mhz ram the board would automatically run the ram @ 667 speeds.
 
^Yes check out if the motherboard supports 800Mhz rams but you can get 800Mhz ram and make them run at 667Mhz, so no issues.
 
Crossx said:
^Yes check out if the motherboard supports 800Mhz rams but you can get 800Mhz ram and make them run at 667Mhz, so no issues.
Click to expand...

That way, when you switch to a newer board, the sticks will run at 800mhz. ;)
 
2.9GHz = 2900MHz

CPU Speed = 200MHz (fsb) x 14.5

Memory being Used = 800MHz --> DRAM = 400MHz

Memory Divider = D = Higher_int(CPU/DRAM) = Higher_int(2900/400) = Higher_int(7.25) = 8

(Higher_int() <--> Higher Integral Value o the Value inside the function)

Thus practical DRAM Speed = 2900/D = 2900/8 = 362.5MHz

Practical Memory Speed = 2x DRAM = 725MHz

Thus 800MHz will wok at 725MHz

with similar way.. 667MHz will work at 644MHz

Solution:

Set FSB = 208MHz (Default 200MHz)

Set Multiplier = 14x (Default 14.5x)

Result:

CPU Speed = 208x14 = 2912MHz (Default)

Memory Speed = 832MHz (for Default 800MHz)

CPU speed wont be compromised.

Memory will run little above rated (832 is doable on most standard memory)

No voltages need to be altered and system shall perform as good as expected.
 
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Awesome madnav..... repped... just a doubt here..

how do i calculate my current memory speed ??? or memory speed in genera [832 the one u calcuated for 208x14=2912]l??

Also how to find out at what speed my ram is running currently ie. 644 or 667 [the old ram that i use]??

Ps. DDR2 800 Dual channel Memory DIMM supported on my mobo... do i still have to do the above setting , i think i have to??

In CPUZ memory timings DRAM frequency is still showin 323.5 even after i changed ht link to 208 n multiplier to 14..
 
HoliC said:
Awesome madnav..... repped... just a doubt here..

how do i calculate my current memory speed ??? or memory speed in genera [832 the one u calcuated for 208x14=2912]l??

Also how to find out at what speed my ram is running currently ie. 644 or 667 [the old ram that i use]??

Ps. DDR2 800 Dual channel Memory DIMM supported on my mobo... do i still have to do the above setting , i think i have to??

In CPUZ memory timings DRAM frequency is still showin 323.5 even after i changed ht link to 208 n multiplier to 14..
Click to expand...

yes that is because you are using 667MHz chip.

200 x 14 / 333 = 8.408

Thus D = 9

Thus current DRAM speed = 208 x 14 / 9 = 323.5MHz

there is no difference because integral value of D calculation with both 14x and 14.5x are same in case of 333MHz DRAM
 
What if i use 224 x13 = 2912. its still gives me 832Mhz to work with.

Also does increasing the HTlink even by a slight amount cause any difference in workin..

or any type of harm to the system..???

Tnx in advance.. :)
 
^^ suggested 208 x 14 so that no voltages will have to be changed..

for 224, HT link speed will be = 1120MHz (Default is 1000MHz)

and FSB will be 224MHz (Default 200MHz)

for this setup to work properly... you will have to increase voltages for cpu and chipset.

(read as risk ...as compared to stock voltages)

the only advantage will be overclocked HT link which will not be noticeable in most scenarios

increase FSB only if you want to reach higher goals with RAM and CPU OCing :)

else try to keep HT link as close as possible to 1000MHz (reducing HT link multiplier with FSB 224 will result in HT link dropping below 900MHz... no advantage + unnecessarily OC of FSB it seems)

for best stock performance keep 208 x 14 ..nothing compromised and voltages will be unchanged too.
 
Okay thnks a lot ya.. :) this is really really valuable info..

Achcha one last question..

I have Transcend 1GB 667 x 2 - Dual channel n im plannin on buyin Corsair xms2 2gb 800 x 2 dual channel..[4 slots total]

Will they work perfectly together n will the corsair RAMs run at 800mhz.
 
SHudnt each of them run at their own individual speed

667 at 667

and the 800 at 800mhz speed..
 
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