Help!:Dynamic Memory Divider

[Sup3rman]

I have some ram which seems to ignore my BIOS memory clock settings. when I set my FSB to 250 and Memory Clock to 200, I actually only 196 memory frequency because a memory divider was applied CPU/14?

It seem my memory clock is adjusted to keep the ram at or round 200MHz. If I replace the this ram with the same BIOS settings I get the correct memory frequency for my BIOS settings.

I have tried flashing my BIOS but that didn't help. I thought the BIOS dictated to the RAM, but is this case the ram seem to be telling the BIOS what to do.

Can some please educate me on what's happening here?

[pik-ard v1.1]

what other options do you have for setting your ram at different dividers?

[Sup3rman]

Max Memory Timing(MHz): [200]
1T/2T Memory Timing: 1T
TCL: 2.0
TRCD: 2
TRAS: 5
TRP: 2

[Sup3rman]

More info:
I have a MSI NEO2 Plat., the memory I'm having an issue with is PC2700.
After setting Max Memory Timing(MHz): [200] in the BIOS, both windows and memtest report memory frequincy as "CPU Ratio/11" "CPU Ratio/12" "CPU Ratio/14" depending on the which CPU multi I use 9,10,or 11.

All other "Max Memory Timing(MHz):" options (Auto,166,133,100) calculate the correct memory frequency.

I there any way I can prevent Max Memory Timing(MHz): [200] from defaulting to Max Memory Timing(MHz): [166]?

[scorp]

the numbers you see are in fact dividers
that means :

200 = 2:1
166 = 5:3
133 = 4:3
100 = 1:1

If you need more informations about what mem. freq. you get for a multiplier / divider combination just searc this forum. There is a page with a complete multiplier / divider table.

[bachus_anonym]

It seems that you're another of those people that have tried to use DDR333 (PC2700) memory and have problems with it on Neo2.

I would assume that PC2700 is just not the kind of memory that Neo2 likes to work with. If you get correct speeds once you replace that RAM with different set ( I believe at least DDR400 / PC3200 ) then that would be proof of what I said above.

[pik-ard v1.1]

the numbers you see are in fact dividers
that means :

200 = 2:1
166 = 5:3
133 = 4:3
100 = 1:1

If you need more informations about what mem. freq. you get for a multiplier / divider combination just searc this forum. There is a page with a complete multiplier / divider table.
no...
200 is 1:1
166 is 6:5
133 is 3:2
100 is 2:1

[scorp]

Believe me .. I know what I am talking about :D. The numbers are the ones I gaved above.

Accordingly to your numbers there is abs. no way to get 100Mhz :)). If 200 is 1:1 => your "166" is 240, your "133" is 300 and finally your "100" is 400. No offense, but before contradicting something please make the math.

[bachus_anonym]

Believe me .. I know what I am talking about :D. The numbers are the ones I gaved above.

Accordingly to your numbers there is abs. no way to get 100Mhz :)). If 200 is 1:1 => your "166" is 240, your "133" is 300 and finally your "100" is 400. No offense, but before contradicting something please make the math.
actually, i think that you're wrong...
this is complete table of memory dividers:

200 (1:1)
183 (9:10)
166 (5:6)
150 (3:4)
133 (2:3)
100 (1:2)

[haPpydUde]

um no scorp you really are wrong. As do the math this way 166/200 = .83 now times that by the mhz ur running at to get ur ram freq. This is all assuming ur using ur stock multi. 200 is 1:1 166 is 6:5 133 is 3:2 100 is 2:1. Yes i know its kinda anoying how it doesnt say 1:1 ect but hey its not that hard once ya get used to it. I just thought i'd let you know.

[haPpydUde]

ya lol post at the same time :toast:

[scorp]

It depends from motherboard to motherboard. The nu bers I gaved are displayed by the BIOS of my A8V. ASUS seems to calulate the total DDR speed. So if you chose 200 MHz FSB and 2:1 (200) divider you will get 400MHz for memory. If you chose 200 MHz FSB and 5:3 (166) divider you will get 333 MHz. That is why I gaved those numbers. Not 100% sure on how they are displayed on other motherboards (on most they are not displayed at all in fact).

Look at this link for example (for the available options on the A8V) : http://www.pcstats.com/articleview.cfm?articleid=1617&page=3

And I've found the memory actual frequency / multiplier thread :) http://www.xtremesystems.org/forums/showthread.php?t=41595&highlight=memory+divider+table

[bias_hjorth]

All you guys are pretty much wrong :D
Take a look a this table OSKAR_WU made:
http://oskarwu.myweb.hinet.net/A64Divider.jpg

Now you can you this as an example I made on my a64 @ 3700:
11cpu multi x 200htt = 2200overall cpu speed / 169 memoryspeed according to the over table = ~ 13 memory divider

Now the memory speed overclocked:
11cpu multi x 274htt = 3014overall cpu speed / 13 memory divider = ~ 231 final memory speed.

[bachus_anonym]

I think this table is a lot easier to read... It makes caclulating your REAL memory speed a lot quicker... It's not complete, but still good.

I'm not sure who made it, though. I just found it somewhere on the net some time ago ;)

http://www.xtremesystems.org/forums/attachment.php?attachmentid=24030&stc=1

[Holst]

I have some ram which seems to ignore my BIOS memory clock settings. when I set my FSB to 250 and Memory Clock to 200, I actually only 196 memory frequency because a memory divider was applied CPU/14?

It seem my memory clock is adjusted to keep the ram at or round 200MHz. If I replace the this ram with the same BIOS settings I get the correct memory frequency for my BIOS settings.

I have tried flashing my BIOS but that didn't help. I thought the BIOS dictated to the RAM, but is this case the ram seem to be telling the BIOS what to do.

Can some please educate me on what's happening here?

Back to the initial problem.

Because your ram is PC2700/2100 the bios wont let you choose 1:1 at antyhing above 166htt as that will put the ram out of spec.
At 200HTT the bios "helpfully" drops the ram devider into 5:6 mode (166) so that you dont overclock your ram...

Obviously this stinks as an overclocker as you cant run 1:1 above 166HTT.

The easy solution is to boot at 166 with the ram at 1:1 then use clockgen to increase the HTT to a higher value.

As for all this confusion over half multiplyers.
Lesson 1 - They are pointless.
Lesson 2 - As they are pointless never use them.

Thats all you need to know.

[pik-ard v1.1]

scorp, with a cpu with a stock speed of ##x200, where ## is the multi, 1:1 will always set the ram at 200mhz (at stock speeds), for DDR400. it has always been thus.

adding on to what holst said, sup3rman, what i suggest you do, is lower the multi, raise the HTT, lower the HTT multi (2-3x), and just let the ram run at a multi, and it will get over 200mhz. (or... should)

[scorp]

I have already explained above why I've said 2:1 = 200MHz. In ASUS BIOSes (for A64s) the dividers are given in such a manner that you obtain the FULL memory frequency, hence :

2:1 with a 200 MHz bus will give you 400 MHz memory frequency. And this is the FULL memory frequency, not to be multiplied by 2 again. If you were to chose 1:1 you will actually get 200 MHz FULL memory frequency. However this is true on ASUS motherboards and not necessarly on others as most other manufacturers won't give you the actual divider, but will rather prefer to give you the frequency (200, 166, 150, 133 etc).

[pik-ard v1.1]

i was just explaining what standard convention is. ;)

[Zanr Zij]

I have some ram which seems to ignore my BIOS memory clock settings. when I set my FSB to 250 and Memory Clock to 200, I actually only 196 memory frequency because a memory divider was applied CPU/14?

It seem my memory clock is adjusted to keep the ram at or round 200MHz. If I replace the this ram with the same BIOS settings I get the correct memory frequency for my BIOS settings.

I have tried flashing my BIOS but that didn't help. I thought the BIOS dictated to the RAM, but is this case the ram seem to be telling the BIOS what to do.

Can some please educate me on what's happening here?


U can run 1:1 with PC2700 ( although Ur can can run higher than PC3200 ) . Note that. So if ur CPU mul ti is 9, ex 200x9 =1.8GHz. Ur ram ratio : 1.8GHz/166 ~ 11 :) so on