Odd divisor correct and what it does.

[CapFTP]

It seems like ozzi and OPB got fooled a bit by this option in the other thread It could have been so beautiful

ehe.....have to say I really read with interest that topic....really well done, but with so many Options in BIOS ...just the Tony straight look can help..

From some playing here it all depends on your CPU HTT as to what this option will do, my initial request to Oskar was to give us something else to play with as write cas is useless as DDR1 only supports a write cas of 1, I had tested a little with the refernece ATI boards which have all the tweaking options and we did find ODC to have some uses.

Regarding this option is actually not so clear to me the really intent of Tony and Oskar...but perhaps trying and looking at sandra and so on I can understand

[xgman]

This thread is making my head spin. (well more than normal anyway)

So say if I run 289x11 at dram set 200 (1-1), is there any reason to use this bios with this option on, to gain bandwith over the 329 bios? Sounds like no right?

[RyderOCZ]

This thread is making my head spin. (well more than normal anyway)

So say if I run 289x11 at dram set 200 (1-1), is there any reason to use this bios with this option on, to gain bandwith over the 329 bios? Sounds like no right?

Only if you know the CPU will run more, but the ram is holding you back, enabling this option would give you a 12 divider and slow the ram down slighly (possibly less than enabling a divider) thus allowing you to push up just a bit more and max everything out.

[ozzimark]

This thread is making my head spin. (well more than normal anyway)

So say if I run 289x11 at dram set 200 (1-1), is there any reason to use this bios with this option on, to gain bandwith over the 329 bios? Sounds like no right?

if you use those settings, and then enable odd divisor correct, the ram will be running at 265mhz instead of the 289mhz it should, as it will change the memory ratio from cpu/11 to cpu/12. nothing more

[Cooper]

Any linky to that BIOS ? Cant` find i myself

[RyderOCZ]

http://www.xtremesystems.org/forums/...ad.php?t=95464

[ozzimark]

i take it from the silence before about this that it's not possible to replace the ratios in the bios with actual memory dividers, like "cpu/5" all the way up to "cpu/50"?

still no answer?

[nn_step]

Very Interesting, SO I can make my Ram Go Faster yet not show that it is going faster...

[RyderOCZ]

Very Interesting, SO I can make my Ram Go Faster yet not show that it is going faster...

No...it shows your ram going fast...but its actually going slower.

@ Ozzimark,

No that is not possible due to the way that CPU speed / Memory speed is calculated on the board, simply doing something like that in the bios is not possible.

[ozzimark]

No that is not possible due to the way that CPU speed / Memory speed is calculated on the board, simply doing something like that in the bios is not possible.

oh well. it would have been nice, but i guess too much to ask for

btw, 4x cpu multi and enabled... gives some amusing results



the ram speed is actually 283mhz

[[cTx]Philosophy]

So correct me if im wrong,but this is a bios error? or was this placed in there intentionally to try to fool ppl into thinking there actually running at said speeds, kinda like the umm whats its name, memory compatability thingie that downclocks the ram like this?
Except this actually shows ram speeds as being something there now, whereas compatability shows downclocked speeds..

[bachus_anonym]

I honestly think making ODC (OddDivisorCorrect) available in this BIOS was a mistake I mean, from the memory evaluations or speed records point of view No software detects it, which is really bad... It might make people either (1) get excited about the clocks that are in fact lower that what they see or (2) "cheat" with max clocks...

From now on, I personally will not trust any max clocks screenshots (stable or not) or memory evaluations done with "406" BIOS and odd multipliers...

[RyderOCZ]

the ram speed is actually 283mhz

Lowest Ram divider is 5 so if you use the 4 CPU multi...its automatically running slower than the FSB (you are actually running CPU/5) and then with ODC enabled you are CPU/6

Remember...ODC has no effect if your CPU multi is even and you are 1:1 (Memclock 200)

[RyderOCZ]

So correct me if im wrong,but this is a bios error? or was this placed in there intentionally to try to fool ppl into thinking there actually running at said speeds, kinda like the umm whats its name, memory compatability thingie that downclocks the ram like this?
Except this actually shows ram speeds as being something there now, whereas compatability shows downclocked speeds..

Not a bios error, it is a feature within the AMD memory controller, just like all the other settings that DFI has given access too, this feature was purposely "unhidden" in this bios.

[RyderOCZ]

I honestly think making ODC (OddDivisorCorrect) available in this BIOS was a mistake I mean, from the memory evaluations or speed records point of view No software detects it, which is really bad... It might make people either (1) get excited about the clocks that are in fact lower that what they see or (2) "cheat" with max clocks...

From now on, I personally will not trust any max clocks screenshots (stable or not) or memory evaluations done with "406" BIOS and odd multipliers...

Understood Bachus, it is still a register that can be read, thus CPU-z and other software could be made to detect it, its just not detected at the moment.

Not to mention, other than a "Max Memory speed screenshot" you would see it in the lack of performance from SuperPi, Sandra, etc.

[bachus_anonym]

Understood Bachus, it is still a register that can be read, thus CPU-z and other software could be made to detect it, its just not detected at the moment.

True, but it's just gonna mess with people's heads. Just as it is now with ratios 233/250 and those have been around for a while now. No software reads memory speed if one chose those "upclocks" so I do not expect CPU-Z, Clockgen, Sandra, Everest, CBUID, etc being updated this time either...
I just really don't understand why people would need this option and why Oscar Wu decided to unhide it To me, it has been totally unneccesary... But it's just me, what do I know

EDIT: I just realized that CPU-Z 1.32 detects ratios 233/250 But still, look how long it took for this to happen and nothing besides CPU-Z 1.32 and up shows it...

[ozzimark]

Lowest Ram divider is 5 so if you use the 4 CPU multi...its automatically running slower than the FSB (you are actually running CPU/5) and then with ODC enabled you are CPU/6

Remember...ODC has no effect if your CPU multi is even and you are 1:1 (Memclock 200)

careful there, you just contradicted yourself. i showed the ONLY case where the last statement is false.

btw, i did calculate the real speed correctly, no?


as a side note, i think we should start changing our focus from pure mhz to highest bandwidth

[RyderOCZ]

careful there, you just contradicted yourself. i showed the ONLY case where the last statement is false.

True...because you used the 4 CPU multi which does not exist in the ram divider table.

btw, i did calculate the real speed correctly, no?

I have no clue if you calculated 283 correctly....no CPU speed in your Screenie to go by

[ozzimark]

True...because you used the 4 CPU multi which does not exist in the ram divider table.

yup, though i thought of something. AM2 is supposed to support ddr2-800, or 400mhz stock. they're also bringing semprons over.. slowest sempron is 1.6ghz. to get 400mhz from 1.6ghz, there's gotta be a cpu/4...
and for all the 1.8ghz CPUs, a cpu/4.5 is needed for 400mhz.. /5 gives 360mhz (similar thing for 2.2, 2.6, 3, etc)

so in short.. will we see 1/2 memory dividers in the new memory controller?

I have no clue if you calculated 283 correctly....no CPU speed in your Screenie to go by

oops, i could have sworn i included a cpu-z validation before the picture on me
cpu-z validation
http://valid.x86-secret.com/show_oc?id=86232

[RyderOCZ]

Not to get into an AM2/DDR2 discussion here...but its not going to work like that....I don't think...unless the base clock on the CPU is 400 instead of 200. What you will probably see is like current Intel boards, you get bigger upclock ram ratio's.

I totally admit to not reading most of the AM2 pre-release material, so if you already know what I just said to be wrong......don't to much

EDIT: Yep 283.5 ram speed

[ozzimark]

Not to get into an AM2/DDR2 discussion here...but its not going to work like that....I don't think...unless the base clock on the CPU is 400 instead of 200. What you will probably see is like current Intel boards, you get bigger upclock ram ratio's.

I totally admit to not reading most of the AM2 pre-release material, so if you already know what I just said to be wrong......don't to much

i sadly don't know much about anything though i hear something about pre-release material? mind lighting the way to such information? give me something to read as a bedtime story

but yeah, i'm figuring it'll be an upclock ratio similar to what we can use with revE, except going all the way up to 2:1... but with stock ram speed being claimed to be ddr2-800.. well, there's gotta be a way to get stock ram speed with stock cpu speed

one thing that wouldn't surprise me completely, is if the memory controller is asynchronous in a way, similar to what nvidia's intel chipsets do.. but i'm not sure if AMD is planning on going that route or not..

[gsan]

got a problem there. i'm using vinny 3200+ with 10x multiplier. now i oc 300x9 with 166 divider, i suppose to get 250 for the ram speed but in fact i got 245.5 only. why huh? mobo is revAD0 with bios 704-2BTA.

[RyderOCZ]

got a problem there. i'm using vinny 3200+ with 10x multiplier. now i oc 300x9 with 166 divider, i suppose to get 250 for the ram speed but in fact i got 245.5 only. why huh? mobo is revAD0 with bios 704-2BTA.

166 mode is 5:6 divider.

9 CPU multi x 6 / 5 = 10.8 which rounds to 11, so memory divider is 11

2700 / 11 = 245.5....that is why ram is 245

[gsan]

166 mode is 5:6 divider.

9 CPU multi x 6 / 5 = 10.8 which rounds to 11, so memory divider is 11

2700 / 11 = 245.5....that is why ram is 245

oh... i tot is 300htt multiple 5 and then divide by 6... haha

[Jester FPS]

166 mode is 5:6 divider.

9 CPU multi x 6 / 5 = 10.8 which rounds to 11, so memory divider is 11

2700 / 11 = 245.5....that is why ram is 245

wait, where did you get 2700?

In his example he said he overclocked to 9 * 300 = 2700

edit: ohh right, so many layers of math to this game.