RAM Divider

Sorry if this is a stupid question, but I could not find the answer...my head started to hurt after a while, heh.

When I set my RAM to 266Mhz that means it is running at a 133 divider correct?

Hopefully that is right because on my A8N-SLI Premium there is no option for a "divider" only RAM speed.

Any help is greatly appreiated!

Also I am using infinitevalence's OCing guide, and my A8N-SLI Premium with a 3800+ X2 with a 133 divider only hits a 220x5 HTT and a max of 230 FSB. I have the PCI Bus locked and everything at stock volts. I don't know what I did wrong.

JohnyRangr said:

When I set my RAM to 266Mhz that means it is running at a 133 divider correct?

Hopefully that is right because on my A8N-SLI Premium there is no option for a "divider" only RAM speed.

Also I am using infinitevalence's OCing guide, and my A8N-SLI Premium with a 3800+ X2 with a 133 divider only hits a 220x5 HTT and a max of 230 FSB. I have the PCI Bus locked and everything at stock volts. I don't know what I did wrong.

Click to expand...

On that board 133 is a divider.
FSB x multi = CPU speed
FSB x divider = Memory Speed.

You don't say what multi you are using so I have no idea what is happening with your OC.
The A8N32 has some similar BIOS settings to the A8N. See:http://www.ocforums.com/showthread.php?t=468038
For info on the A8N-SLI-D, See:http://www.hardwareanalysis.com/content/topic/38623/

Sorry if I am speaking in riddles, I am a noob at overclocking. My memclock speed will only go as low as 200Mhz. I can't find anything else that will let me go down to 133. As for the multi on the CPU I am using 6x to find out my max HTT and FSB like the guide says. I havn't even gotten to overclocking the CPU yet because those numbers seem kind of low too me. The HyperTransport frequency I ran it at 5x to find the max HTT then at 3x to find the max FSB.

I don't know if I am doing it right though.

JohnyRangr said:

Sorry if I am speaking in riddles, I am a noob at overclocking. My memclock speed will only go as low as 200Mhz. I can't find anything else that will let me go down to 133. As for the multi on the CPU I am using 6x to find out my max HTT and FSB like the guide says. I havn't even gotten to overclocking the CPU yet because those numbers seem kind of low too me. The HyperTransport frequency I ran it at 5x to find the max HTT then at 3x to find the max FSB.

I don't know if I am doing it right though.

Click to expand...

Not really.

billb said:

Not really.

Click to expand...

Sorry...could you tell me how I am supposed to do this. I really would appreciate it.

JohnyRangr said:

Sorry...could you tell me how I am supposed to do this. I really would appreciate it.

Click to expand...

Sure....

So ya wanna overclock huh?
http://www.ocforums.com/showthread.php?t=468038
http://www.extreme.outervision.com/psucalculator.jsp
http://amd64oc.blogspot.com/
http://www.overclock.net/overclock.p...king-guide.htm
http://overclock.net/amd-general/91-...ing-guide.html
http://www.overclock.net/faqs/96478-...verclocks.html
http://www.anandtech.com/memory/showdoc.aspx?i=2223&p=5
http://www.dfi-street.com/forum/show...79&postcount=4
http://forums.extremeoverclocking.co...d.php?t=151373
http://www.pcstats.com/articleview.c...eid=873&page=1
http://www.rojakpot.com/freebog.aspx
http://www.ocforums.com/showthread.php?t=472527
http://vip.asus.com/forum/view.aspx?...Language=en-us
http://www.overclock.net/graphics-ca...does-help.html
http://forums.amd.com/index.php?showtopic=67749
http://www.corsairmicro.com/corsair/...707/index.html
http://www.overclock.net/faqs/119265...save-your.html
http://www.elecdesign.com/Articles/I...ArticleID=9611

Usefull OC programs:
http://www.xtremesystems.org/forums/...ad.php?t=96678
AMD64 Calculator: http://www.geocities.com/edgemeal_software/
http://math.gogar.com/athlon64.cgi
http://www.gurushane.com/site/software.aspx
http://www.cpuid.com/cpuz.php
http://www.memtest86.com/
http://www.xtremesystems.com/pi/
http://www.thecoolest.zerobrains.com...opic.php?t=137
http://www.ocxtreme.org/forumenus/showthread.php?t=2945
http://www.softwarepatch.com/windows/index.html

More usefull info:
http://forums.procooling.com/vbb/sho...ght=120mm+fans
http://www.driverheaven.net/guides/testingPSU/
http://forums.extremeoverclocking.co...d.php?t=228978
http://www.ocforums.com/showthread.php?t=468767
http://www.ocforums.com/showthread.p...92#post4672492

JohnyRangr said:

Sorry...could you tell me how I am supposed to do this. I really would appreciate it.

Click to expand...

The RAM speeds listed on your board are the DDR speeds, i.e. twice the actual RAM clock. Therefore, putting the memory clock setting at 400 will run the memory 1:1 with your FSB. The lowest divider on your board is DDR200, which will run the memory roughly half as fast as the FSB (1/2 divider). Other dividers are DDR333 (5/6 divider) and DDR266 (2/3 divider). You really should read through some of those overclocking guides and try to understand everything before you start to play with the settings, though.

Billb, thank you so much for all those links they helped a lot!

Killr, I kind of figured that is what they ment but I was not sure, thank you.

Those are great links that billb provided!

billb said:

On that board 133 is a divider.
FSB x multi = CPU speed
FSB x divider = Memory Speed.

Click to expand...

Actually that is a formula for Intel's.
The formula for that 3800 works like this
HTT * Multi = CPUMhz / RAM (divider) = Ram Speed.

Your Mobo Bios May Vary

220 * 10 = 2200 / 15 = 146.6 = DDR296 .(133 divider)
220 * 10 = 2200 / 12 = 183.3 = DDR366 .(166 divider)
220 * 10 = 2200 / 11 = 200 = DDR400 ...(183 divider)
220 * 10 = 2200 / 10 = 220 =DDR440 ....(200 divider so called 1:1)
220 * 10 = 2200 / 9 = 244.4 =DDR488 ...(216 divider)
220 * 10 = 2200 / 8 = 275 =DDR550 ......(233 divider)


Forget that ratio stuff, it'll just mess up your brain!

AlabamaCajun said:

Actually that is a formula for Intel's.
The formula for that 3800 works like this
HTT * Multi = CPUMhz / RAM (divider) = Ram Speed.

Forget that ratio stuff, it'll just mess up your brain!

Click to expand...

The actual formula for A64 memory is:
Multi X FSB / (Multi x 200/Divider rounded up)

220 * 10 = 2200 / 15 = 146.6 = DDR296 .(133 divider)= 146.6
220 * 10 = 2200 / 12 = 183.3 = DDR366 .(166 divider)= 183.3
220 * 10 = 2200 / 11 = 200 = DDR400 ...(183 divider) = 200
220 * 10 = 2200 / 10 = 220 =DDR440 ....(200 divider) = 220
220 * 10 = 2200 / 9 = 244.4 =DDR488 ...(216 divider) = 220
220 * 10 = 2200 / 8 = 275 =DDR550 ......(233 divider) = 275

You are correct about the ratios they just confuse. But the A64 memory controller can not handle fractions, hence the (Multi X 200/Divider) expression has to be rounded up to the next highest whole number. Usually this is of little consequence, but sometimes is a significant difference.

Download Blue's AMD Athlon 64 Overclocking Calculator and see the results of both calculation methods.
http://www.gurushane.com/site/software.aspx The ceil (rounding up) method yields results that agree with CPU-Z and benchmarks with Sandra.

On my venice clocked at 2000 and Golden dragons on 216 divider (CPU/9) produced 216 MSI RS480 board (Now has a 4000SD in it).

billb said:

The actual formula for A64 memory is:
Multi X FSB / (Multi x 200/Divider rounded up)

Click to expand...

Also don't use FSB, the FSB on our example chip above is running at 2200. HTT is only part of the Clock Gen.
That forumla is the full version, that is how I got the dividers for ram but it only works on AM1s. AM2 uses 400 as the Base ram timing [edit] (200 for the formula)[/edit]. As for the rounding up or down (mine are mostly rounded down), it depends on your BIOS so we both stand corrected. I've been saying BIOS's need to start opening up the divider to user control so we can get more use out of them.

JohnyRangr said:

Sorry if I am speaking in riddles, I am a noob at overclocking. My memclock speed will only go as low as 200Mhz. I can't find anything else that will let me go down to 133. As for the multi on the CPU I am using 6x to find out my max HTT and FSB like the guide says. I havn't even gotten to overclocking the CPU yet because those numbers seem kind of low too me. The HyperTransport frequency I ran it at 5x to find the max HTT then at 3x to find the max FSB.

I don't know if I am doing it right though.

Click to expand...

That guide worked fine for me, a simple step-by-step that helps you get familiar with the different settings, where they are on your board, and a little about how they interact. It's a very good starter so you're not over-whelmed with numbers and options. Just remember one very important thing - write down your settings and results, even if they don't work!

Thanks billb for the great list - saved in favs ...!

AlabamaCajun said:

On my venice clocked at 2000 and Golden dragons on 216 divider (CPU/9) produced 216 MSI RS480 board (Now has a 4000SD in it).

Also don't use FSB, the FSB on our example chip above is running at 2200. HTT is only part of the Clock Gen.
That forumla is the full version, that is how I got the dividers for ram but it only works on AM1s. AM2 uses 400 as the Base ram timing. As for the rounding up or down (mine are mostly rounded down), it depends on your BIOS so we both stand corrected. I've been saying BIOS's need to start opening up the divider to user control so we can get more use out of them.

Click to expand...

I'm confused by your reply.

"the FSB on our example chip above is running at 2200."
I'm not aware of any MOBOs that can run a FSB over 500, much less 2K.

"HTT is only part of the Clock Gen."
I never mentioned Clock Gen...that's a whole other issue.

"AM2 uses 400 as the Base ram timing"
I don't think so.

"As for the rounding up or down (mine are mostly rounded down).
You can round any way you like, but you will only get the true memory speed by rounding up.

"it depends on your BIOS"
BIOS has nothing to do with how memory speed is calculated.

"BIOS's need to start opening up the divider to user control"
With Dividers and 1/2 multis there is all the control you could possibly want. One Clk dividers are not a possibility because of the basic architecture of A64 memory controllers.

FSB is actually the cross bar on die in A64 and Opteron processors. This crossbar runs at CPU speed and interconnects the CPU to memory controller, HT(IO) and other Cores.
What people call FSB on 939 and AM2 is actually HTT which is just the frequency is multiplied up to the CPU frequency by a clock generator.

Both my AM2 systems 400, 533, 667 and 800 on the memory timing side. These translate to 200, 266, 333 and 400. I'll have to check but the BIOS may use 200 as the Base timing which I was thinking of half 800 or 400. *Corrected the previous post.

The on cpu divider is not set to 400, 533, 667 or 800. These show to use as a choice list which is converted to a divider that get sent to the memory controller/divider. I would like to plug the divider directly into the controller and bypass those memory speeds. I have a 939 Venice that has the clocks stock at 2000. At 200 setting the ram divider is 10. The next setting down is 166 which is ram divider 12. (billb is correct rounded up). I want to use 11 because I could crank the 2750 putting my ram as DDR500 it's rated speed. * HHT=275, CPU = 2750 / 11 = 250 * When you get to AM2 there are a number of dividers between 200 and 400 that can be attained but the bios only gives 4!

Need that 183/366 setting, huh ...?

QuietIce said:

Need that 183/366 setting, huh ...?

Click to expand...

Yes, dangit! That one and a bunch of others. What is nice on the Infinity M4, the BIOS shows you the result speed while in setup!