Is there any way i can find out if my mobo supports dual ddr memory?

Ronaldo7

My board is a msi 648 max without ht. It can support ddr 333 memory. i currently have 1 stick of Twinmos 512mb pc2700 cl2.5 memory in there and i would like to get another 512mb stick. Should i get the exact same type or ditch both and get two ddr pc 3200 cl2 512mb modules?

Matt Simis

Very easily: Just search on google for "msi 648". The top links are all reviews, none of which mention dual channel.

There were no dual channel "DDR333 motherboards" for the P4 anyhow. What has the question about dual channel got to do with using 2x PC2700 or 2x PC3200 sticks? If your board was DC capable then either setup would run in Dual Channel mode.



Matt


PS: "Dual DDR memory" assumed to mean Dual Channel, as all boards are at least meant to operate with 2 Dimms if not 3, as long as they have the required number of slots.

Ronaldo7

What has the question about dual channel got to do with using 2x PC2700 or 2x PC3200 sticks?

You misunderstood me or i didnt make it clear enough. If i have pc 2700 ram in my system and i add a 512mb dimm of pc 3200 ram then wont the pc 2700 ram slow it down to pc2700 ram and not pc 3200?

Is there much of a difference between pc2700 ad pc 3200 ram?

i_am_dogboy

I dont think there are any motherboards that control every memory slot separately and allow different speeds on each. So in answer to your question, the pc3200 would have to run at 2700 if you intend to put them in the same motherboard. Not sure about the difference in performance thought, have a look on anandtech and tomshardware at some memory reviews to see for yourself.

Col_Loki

Basicly if your running your 533mhz (133mhz x 4 - quadpumped)FSB chip at stock that means the Ram is going to be running at 133mhz (266mhz DDR)...

Which means if you put in Pc3200 (DDR400) it will only run at Pc2100 (DDR266)...... The only point in even having Pc2700 is if you are overclocking. Granted you might get slightly tighter timings because you will be running it at a lower speed.

Sir Random

If the board only supports DDR333, then you may not be able to run DDR400 at it's rated speed anyway.
Is the CPU 533Mhz? If so, it's probably running the DDR333 at 166 with a 4:5 divider (CPU/SDRAM 133/166) so you'd need to o/c the cpu to 166fsb to run DDR400 at 200.
Have you tried o/cing the fsb to 166 and running your DDR333 at 1:1? If that's stable, you might get DDR400 to run at 200Mhz with the 4:5 divider.

joePC

Your PC2700 Ram is running @ 333Mhz
If you install PC3200 Ram together with the PC2700 Ram it will run @ 333Mhz.

This is correct, weather or not your FSB is 400Mhz/533Mhz, If your motherboard supports PC2700 Ram then it is running @ 333Mhz.



Your MB does not support Dual channel memory.

The bottle neck is always the slowest component.

Thanks joePC

Col_Loki

This is where things get a little shady for me.......

Is the Pc2700 Ram really running at 333mhz when the FSB is only 133mhz (ie DDR266mhz) , there is no performance increase at all on an AMD system if this is happening so im thinkin it should be simular on the intel ones ??

(Tested this months ago so i dont have figures)
Ie Pc3200 Ram .......
Running 333mhz FSB (166mhz x 2) ....... RAM 1:1 = Same bandwidth as running ram 4:5 it FSB @ 333: RAM @ 400mhz............

I find this one hard to call. Guys shed any light?

joePC

The FSB does not matter when it comes to the MB supported memory speeds. The MB in question supports 400Mhz & 533Mhz FSB P4's.

With AMD boards there is in some cases a increase in preformance if the FSB and memory Fqz is the same e.g.

AMD XP2500 333Mhz FSB with 333Mhz Memory PC2700 would be better than PC3200 ram running @ 400Mhz.

Just because the FSB is one speed doesn't mean the memory speed has to be the same. Its got to do with the MB supported memory speeds.

Thanks joePC

Col_Loki

Yea im aware of that alrite, but i thought the main advantage was if you were overclocking?

The only way i see any point in having Ram running faster than the FSB is mabye when you consider DMA (and im not as well up on this as i should be)?? Would this be a factor as to why you would run your Ram async from FSB??

Mutant_Fruit

My motherboard allows me to set my CPU fsb different to my RAM FSB. i.e. i can set my CPU to the correct settings (133X11) AND then set my ram to work at up to ddr400 speeds. (Then if i overclock the CPU fsb, the ram gets the overclock too, along with everything else.)

I hope thats clear enough.

Matt Simis

Originally posted by COL_LOKI
This is where things get a little shady for me.......

Is the Pc2700 Ram really running at 333mhz when the FSB is only 133mhz (ie DDR266mhz) , there is no performance increase at all on an AMD system if this is happening so im thinkin it should be simular on the intel ones ??

(Tested this months ago so i dont have figures)
Ie Pc3200 Ram .......
Running 333mhz FSB (166mhz x 2) ....... RAM 1:1 = Same bandwidth as running ram 4:5 it FSB @ 333: RAM @ 400mhz............

I find this one hard to call. Guys shed any light?

You forget that P4 systems have more bandwidth available than AthlonXP systems. The slowest P4 is 400MHz (effective) FSB thanks to the quad pumping. The fastest is 800MHz. The P4 can indeed use the extra memory bandwidth of DDR333\400 even when running at 133MHz FSB (as its x4 = 533MHz, not 2x =266MHz like on the AXP).

Dual Channel and DDR400 Memory speeds on AthlonXPs were mainly marketing tactics used by VIA and nVidia. On the Athlon64 and P4, memory speed actaully matters.



Matt

Sir Random

Originally posted by joePC
The FSB does not matter when it comes to the MB supported memory speeds. The MB in question supports 400Mhz & 533Mhz FSB P4's.

With AMD boards there is in some cases a increase in preformance if the FSB and memory Fqz is the same e.g.

AMD XP2500 333Mhz FSB with 333Mhz Memory PC2700 would be better than PC3200 ram running @ 400Mhz.

Just because the FSB is one speed doesn't mean the memory speed has to be the same. Its got to do with the MB supported memory speeds.

Thanks joePC

"Just because the FSB is one speed doesn't mean the memory speed has to be the same. Its got to do with the MB supported memory speeds."

MB supported mem speeds are just different dividers 1:1, 4:5, 2:3 etc.

"AMD XP2500 333Mhz FSB with 333Mhz Memory PC2700 would be better than PC3200 ram running @ 400Mhz"

That's because AMDs don't like asynchronous ram. P4's have no problem running RAM faster than the cpu's fsb.

A 533Mhz P4 runs at 133fsb. Add DDR400 ram and:
With a 1:1 divider, RAM runs at 133 (266Mhz)
With a 4:5 divider, RAM runs at 166 (333Mhz)
With a 2:3 divider, RAM runs at 200 (800Mhz = Default speed)

"Its got to do with the MB supported memory speeds"
MB supported mem speeds are just the supported divider ratios (sometimes needs jumper settings)

Originally posted by joePC
(Tested this months ago so i dont have figures)
Ie Pc3200 Ram .......
Running 333mhz FSB (166mhz x 2) ....... RAM 1:1 = Same bandwidth as running ram 4:5 it FSB @ 333: RAM @ 400mhz............

I find this one hard to call. Guys shed any light?

It's probably due to relaxed timings at 333Mhz.

My DDR400 runs at 333Mhz with 2,6,2,2
At 400Mhz the timings relax to 3,8,3,3
The 333Mhz 2,6,2,2 actually outperforms the 400Mhz 3,8,3,3

Col_Loki

My motherboard allows me to set my CPU fsb different to my RAM FSB. i.e. i can set my CPU to the correct settings (133X11) AND then set my ram to work at up to ddr400 speeds. (Then if i overclock the CPU fsb, the ram gets the overclock too, along with everything else.)

Yea ive used those dividers and tested them out on an AMD sytem and theres absolutly no porformance increase at all (running single stick)...........different on intels .

You forget that P4 systems have more bandwidth available than AthlonXP systems. The slowest P4 is 400MHz (effective) FSB thanks to the quad pumping. The fastest is 800MHz. The P4 can indeed use the extra memory bandwidth of DDR333\400 even when running at 133MHz FSB (as its x4 = 533MHz, not 2x =266MHz like on the AXP).

Thats good to know, cheers matt. God love me stayin with the AMD XP range .......

It's probably due to relaxed timings at 333Mhz.

Ran the same timings with FSB @ 333mhz,
Ram @ 333mhz ....2-3-3-7
Ram @ 400mhz ....2-3-3-7 and when the Ram was running at Pc3200 it was a tiny ammount under the scores of the Pc2700.


Anyone be able to post any benchmarks to see how much extra bandwidth is available by using higher speed memory o nthe intels ??