Complete A64 Memory Divider Table

[Orthogonal]

I know how to calculate everything, but I don't know how to get a memory divider of 13 on my GA-K8NF-9
only options I can find are 133, 166, 200

Unfortunately, not all motherboards give all the different multiplier options.

[DarkManX_BG]

CPU-Z reads it right for me:
I run 300HTT, a multi of 8x and I want 250MHz memory speed. The 166 (5/6) divider should give me 250MHz. However:

200x8 / 166 = 9,xx -> 10
2400/10 = 240MHz memory speed
And that's what CPU-Z reads here...

[P_1]

Or try the spreadsheet cause it can't get any easier...complete with graphs, etc in the separate sheets. Plug yer numbers and it does the rest..

http://www.xtremesystems.org/forums/...ad.php?t=49393

So the neo2 wont work with a 9 multi and the 133 divider? (im trying to get 2800mhz on cpu with ram running at 200 on a 3000+ thats limited to a 9 multi on a neo2)

[Spajky]

How to know the real memory clock on AMD "K8" platform:

... { A64´s have a default clock reference [System Bus] at 2HGz & default mem. divider @ 10, while s.754 Sempron´s at 1,6GHz & divider of 8. That means for Example : running a 50% OC-ed 1,8GHz CPU @ 2,7GHz-(Htt-300MHz) : Sempron with mem.divider 9 & A64 with 11; real memory clock on first one is 267MHz, while on another is 273MHz, if your memory sticks can handle it } ! ...

So; for A64: Htt x [def.div(10) / mem.div.] = real mem.clock
& Sempron: Htt x [def.div.(8) / mem.div.] = real mem.clock

CPU-Z is not reliable on AMD "K8" platform showing memory clock (mem.divider is shown properly!)


My (research) article "about BENCH´ING MEMORY -real life"
with WinRAR´s built_in benchmark & hardware test" - on my site:
some tests/benchmarks & explanation HOW IT WORKS, is here directly:

http://freeweb.siol.net/jerman55/HP/benchMem.htm

[especially the yellow column is interesting!]
/sorry, I didn´t make any graphs/

Regards ...

[T_M]

*breaks out the shovel for some digging*....

Only thing i can find wrong with the table Oskar is that you spelt "Ratio" wrong
Apart from that is seems spot on for my own findings on 10x and 11x.

[ImportantAwareness89]

Ok, so Athlons use this type of divider setting, but Intels still use the simple FSB * ratio right? Only Athlons involve the whole ceiling, multiplier, etc...??

[lukija]

Hi. My first post here

I wrote small utility , you can grab it here:

http://users.yubc.net/~lukija/A64Info.rar

It is still unfinished, untested .... works well on my Winchester. Use it on your own risk. Yes, i know, it has stupid name (A64Info) You can tweak some values like in A64Tweaker and it also has built in calculator which calculates memory speed and I used Oskars table as a starting point.

But, I have one question regarding undocumented dividers. For example 180 ( from the DFI point of view). I'm not sure if it is 183.0 MHz or 183.33..... MHz. According to the table, it is 183.0 MHz. For example, you have 2200 MHz CPU (200 MHz x 11). And use 180 divider on DFI. If we look at the table or use calculator in A64Info we get divider 13 and memory speed of 169.23 MHz. But if we assume that 180 divider implies 183.33..... MHz then we get 12 divider and exactly 183.33..... MHz. It seems logical to me. It would be interesting to measure memory bandwidths in these two scenarios:

1) CPU Speed 2200MHz (220 MHz x 10). Using 166 divider we have 12 memory divider which finally gives 183.33 MHz memory speed. Measure bandwidth using Sandra or Everest. This bandwidth will be used as reference.

2) CPU Speed 2200MHz (200 MHz x 11). Using 180 divider we have:

a - 13 divider (if we assume thah upper limit for memory speed is 183.0 MHz) and memory speed of 169.23 MHz

b - 12 divider (if we assume that upper limit for memory speed is 183.33... MHz) and memory speed of 183.33... MHz

Comparing measured bandwidth in case 2 with one measured in case 1, we could see what is upper limit. If bandwidth in case 2 is equal (+/- few MB/s) to one in case 1 we can say that upper limit is 183.33... Mhz. If bandwidth in case 2 is lower ( because of 14 MHz lower memory speed) then one in case 1 we can say that upper limit is 183.0 MHz.

Required: CPU with at least 11 multi, mobo with 180 divider, Sandra, Everest.

Any ideas, suggestions, comments?

[ReelMonza]

Nice, will check your app later, can you please look at this

[lukija]

Well friend of mine did some tests, CPU is A64 3500+ Newcastle core:

a) 220x10 , 166 divider (183.33 MHz memory speed), using it as a reference value since 166 divider is "clean"

Sandra - 5518/5480 MB/s (integer/float, buffered,SSE2)
Sciencemark - 5079.09 MB/s

b) 200x11, 180 divider, (memory speed is either 183.33 MHz or 169.23 MHz)

Sandra - 5122/5114 MB/s (integer/float, buffered,SSE2)
Sciencemark - 4750.25 MB/s

Since bandwidth is noticeable lower, I think that memory is running at 169.23 MHz thus upper limit for memory clock for 180 divider iz 183.0 MHz rather than 183.33 MHz.

Still I'm waiting for one test - 220x10 with 150 divider which will give memory speed of 157.14 MHz, just to have another reference value to comare with.

Any suggestions?