Explain or direct me to OCing on A64 from the basics

[ITPaladin]

I have a KN8 mb with an Opteron 146.

I do not know what a divider is. I don't know what LDT and HTT are, where to find them, what they do, etc.

In my BIOS, I have in the SoftMenu the section for FSB with multi and PCI-E clock.

Under the Advanced Chipset area you will find:

HT Frequency with settings of Auto, and 1x through 5x.

I went through every page in the BIOS and I didn't find any word of "divider".

The multiplier has a max setting of 10. I don't know if this max setting is the limitation of the BIOS or the CPU.

I can only see raising the FSB in order to overclock since it is maxed at x10.

I did the first step in the A64 thread here of setting the multi to 6, and I set the mhz of the RAM to 100 since you can't set SPD and mhz seperately like Zebo seems to imply to do.

I found according to his calculation, that 221 would be my max safe FSB since at 233 the OS had long load time or locked.
This is only if I am following it correctly.

I wish I could take screenshots of the BIOS to show those of you that are not familiar with this boards BIOS.

 

[Screech]

the 1x through 5x are the LDT things.

the RAM speed works as the divider i believe. I think my board works a bit different so I might be wrong on this one, but 100 is probably the 1/2 divider, and if there is a setting for 166, that is the 5/6 divider. Don't quote me on this part though.

HTT is basically the FSB. When you set it to 221 or 233 or whatever, that is the HTT number. HTT x CPU multi = CPU core speed.

I doubt 221 is your max safe FSB. You probably didnt put your LDT at 4x instead of 5x. You want to keep LDT x HTT from exceeding 1000, and 220 x 5 = 1100.

 

[ITPaladin]

Originally posted by: screech
the 1x through 5x are the LDT things.

the RAM speed works as the divider i believe. I think my board works a bit different so I might be wrong on this one, but 100 is probably the 1/2 divider, and if there is a setting for 166, that is the 5/6 divider. Don't quote me on this part though.

HTT is basically the FSB. When you set it to 221 or 233 or whatever, that is the HTT number. HTT x CPU multi = CPU core speed.

I doubt 221 is your max safe FSB. You probably didnt put your LDT at 4x instead of 5x. You want to keep LDT x HTT from exceeding 1000, and 220 x 5 = 1100.

I had the HT Freq at auto. What should it be at for the first step of finding the "max HTT / FSB"?

I figured that HTT x multi would be the core. I think I will PM Zebo and tell him to step back a notch and explain these new terms and settings in his guide.

I didn't know I had to learn yet another setting moving from XP to 64.

(ok you were editing while I was typing...I should set HT Freq to 1x, set multi to 6 or maybe even 4, then redo the FSB tests? Then when I get max FSB I multiply that by the HT Freq and if it is over 1000, somehow reduce the calculation to 1000?)

 

[Screech]

It (LDT or HTT multi) should be at the highest it can be without making the ((1 2 3 4 or 5) x HTT) from exceeding 1000. So for HTT (or FSB) of 201 to 250, 4x; for 251 to 333, 3x; 334 to 500, 2x; and anything over that, 1x. Realistically, the concept of you getting any of those really high FSB/HTT's on that board is out of the question.

 

[GuitarDaddy]

LDT (Lighting Data Transport) and HT(Hyper transport) are the same thing. At stock for A64's it calculated as HTT(FSB) x HT frequency (LDT) ie... 200 x 5 = 1000. This bus speed affects performance very little, but can cause system instability if you go much over 1000, so as you overclock by raising the HTT you have to lower the HT frequency to keep the total under 1000. So for overclocking from 200-250mhz HTT use the 4x, and for over 250mhz use 3x


Memory Dividers are usually labled "mem clock" or "max mem clock" or "DDR frequency" or something along those lines. The values usually listed as 200,166,133,100 or DDR400,DDR333,DDR266,DDR200


Your HTT being limited to 221 sounds like your AGP/PCI buses aren't being locked when overclocking. To be able to overclock very well at all you need to find out how to lock the buses, which may involve moving you hard drives to different ports

 

[ITPaladin]

ISOLATE Don't forget to take notes. 1. Max HTT/FSB should be first ..*only works if motherboard has locks. Most A64 boards do today. Sata 1 and 2 are not locked on some nforce mobos use 3 and 4. -set CPU multi to 6 or 7, this will take CPU out of equation -set memory to SPD and 100, this will take memory out of equation -Increase HTT/FSB up until you fail to boot or there abouts, back down 5%, (HTT * 0.95), this is your max safe HTT.

I also don't know about any locks on this board. I plugged my SATA cable into channel 4 just in case.

I set the memory to 100, but when I tried to do the second test of finding max chip capable and raising FSB (HTT?) to just 205, it would not boot to Windows. This was with HT Frequency at Auto. When I set the memory setting to SPD instead, then it would allow me to raise the FSB and boot to Windows.

ugh all this guesswork calculation...

It was so simple on XP with just FSB x multi.

 

[ITPaladin]

Originally posted by: GuitarDaddy
LDT (Lighting Data Transport) and HT(Hyper transport) are the same thing. At stock for A64's it calculated as HTT(FSB) x HT frequency (LDT) ie... 200 x 5 = 1000. This bus speed affects performance very little, but can cause system instability if you go much over 1000, so as you overclock by raising the HTT you have to lower the HT frequency to keep the total under 1000. So for overclocking from 200-250mhz HTT use the 4x, and for over 250mhz use 3x


Memory Dividers are usually labled "mem clock" or "max mem clock" or "DDR frequency" or something along those lines. The values usually listed as 200,166,133,100 or DDR400,DDR333,DDR266,DDR200


Your HTT being limited to 221 sounds like your AGP/PCI buses aren't being locked when overclocking. To be able to overclock very well at all you need to find out how to lock the buses, which may involve moving you hard drives to different ports

I already moved the SATA drive with XP on it to channel 4.

I have the HT Freq on auto. I assume it would automatically move the x# down as I move the FSB up?

Perhaps I don't have a setting down right for the 221 since I don't understand this and where to look.

 

[Screech]

Originally posted by: ITPaladin
(ok you were editing while I was typing...I should set HT Freq to 1x, set multi to 6 or maybe even 4, then redo the FSB tests? Then when I get max FSB I multiply that by the HT Freq and if it is over 1000, somehow reduce the calculation to 1000?)

Well, if you go all the way down to 1x, you actually might be able to notice the performance hit. set it down to 4x, and if you push your FSB/HTT above 250, set it down to 3x.

and yeah, like the guide says, put the CPU multi low, like 4 or 6, to take the CPU out of the equation.

EDIT: I'm not sure what the auto would do on that board; better just to set it down to 4x/3x, as said above.

 

[ITPaladin]

From what I understand here, I put the multi to 4, start at 200 MHz, have the HT Freq at x4, and memory at 200 for the first step.

I most definitely have a problem understanding these 3 things.

My system wouldn't boot to Windows with those settings. Is that just because it was too low?

 

[Screech]

If that "200" for memory functions as the 1:1 "divider" (running memory at the same speed as the HTT), then you would want to go down a notch, for example, to 166.

I probably made a mistake in terminology somewhere above, but HTT x HT freq (or LDT multi or whatever you call it) needs to be less than or equal to 1000. So starting at HTT 200, you have 200 x 4 = 800. moving up, you will go through 210 x 4 = 840, 220 x 4 = 880, etc. At 250 x 4, you have 1000 again, and to move the HTT higher, you need to go down to an HT freq of 3x. then you have 260 x 3 = 780, and so on.

I think you are getting confused between the CPU multiplier and the hypertransport; the CPU speed is the CPU multiplier x HTT. Default for an opteron 146 is 10 x 200. The Hypertransport x HT multi or HT freq, or whatever your board might call it, gives you your "FSB" speed. The best way I can explain this is by comparison; the pentium 4 has an FSB of 200, "quad pumped" to 800. The athlon 64 has the HTT x the mulitplier you select. However, while both of these depend on the HTT speed which starts at 200, they are not the same; you want to push the CPU cpeed (HTT x CPU multi) as high as possible (within reason, of course), while you want to keep your total hypertransport/"FSB" (is the correct term LDT? too many terms, indeed) speed from going over 1000. Some motherboards might be able to go higher, but just play it on the safe side

Hope that helps.

EDIT: I see you edited yours as well If it wouldn't boot, I've read of some boards having faulty lower multipliers, so this MIGHT be the cause of the problem. granted, at 800 mhz for the CPU , that would be pretty slow, but windows should be able to run.

 

[ITPaladin]

Originally posted by: screech
1:If that "200" for memory functions as the 1:1 "divider" (running memory at the same speed as the HTT), then you would want to go down a notch, for example, to 166.

2:I probably made a mistake in terminology somewhere above, but HTT x HT freq (or LDT multi or whatever you call it) needs to be less than or equal to 1000. So starting at HTT 200, you have 200 x 4 = 800. moving up, you will go through 210 x 4 = 840, 220 x 4 = 880, etc. At 250 x 4, you have 1000 again, and to move the HTT higher, you need to go down to an HT freq of 3x. then you have 260 x 3 = 780, and so on.

3:I think you are getting confused between the CPU multiplier and the hypertransport; the CPU speed is the CPU multiplier x HTT. Default for an opteron 146 is 10 x 200. The Hypertransport x HT multi or HT freq, or whatever your board might call it, gives you your "FSB" speed. The best way I can explain this is by comparison; the pentium 4 has an FSB of 200, "quad pumped" to 800. The athlon 64 has the HTT x the mulitplier you select. However, while both of these depend on the HTT speed which starts at 200, they are not the same; you want to push the CPU cpeed (HTT x CPU multi) as high as possible (within reason, of course), while you want to keep your total hypertransport/"FSB" (is the correct term LDT? too many terms, indeed) speed from going over 1000. Some motherboards might be able to go higher, but just play it on the safe side

Hope that helps.

EDIT: I see you edited yours as well If it wouldn't boot, I've read of some boards having faulty lower multipliers, so this MIGHT be the cause of the problem. granted, at 800 mhz for the CPU , that would be pretty slow, but windows should be able to run.

Let me address these one at a time:

1. The lowest I can set the RAM MHz is DDR 200, unless there is some modified BIOS out there that will let me go lower, as well as a higher CPU multi...

2. I understand now that HTT = the same as saying FSB and FSBxHT Freq needs to be less than or equal to 1000.

3. #2 addresses some of #3 here as I said I understand CPU speed is multi x HTT(or FSB as the name seems to have changed from XP to A64 now).

I see that the combo of CPU multi X FSB X HT Freq = the new A64 effective FSB, correct?

I upped FSB and now can start to boot. I am on 230 right now.


BTW, Ever since I started this my speaker has been beeping at me. On reboot from Windows, I get what sounds like 2 short and 1 long. I wish they wouldn't run the beeps to close together...
On reboot from BIOS, I get what sounds like 2 long and then the one short which sounds like the regular POST beep.

Even when setting everything back to what it was, except for the power mgmt functions of fan speeds, etc, it still beeps.

 

[ITPaladin]

ok listened again on this reboot to 235 and it is always doo doo DAAH...dot....

I suppose that is two short and one long plus the POST beep.

 

[Screech]

1: Your mobo must address memory speeds as GuitarDaddy said above: DDR400,DDR333,DDR266,DDR200. DDR400 = 200, DDR333 = 166, and so on. DDR means double data rate; basically, dividing this by 2 will give the "normal" speeds.

2. Perhaps LDT is the name of the HTT x HT freq; assuming this is correct then:

3. The athlon 64 efective FSB (or LDT, if the above is correct) = FSB x HT Freq, and is what in #2 must stay below 1000. The CPU multiplier doesn't come into play for the effective FSB.

I get a beep here and there; As long as my computer runs stably, I figure it is better left alone. Not totally sure what to make of the different beepings, though.

 

[ITPaladin]

I changed the fan stuff / CnQ, etc to optimized defaults and the beeps went away. I guess it doesn't like me not being Mr. Safety.

up to 240 Mhz now...I guess I can get it higher with lower multi now.

 

[ITPaladin]

passing 300 Mhz now

 

[ITPaladin]

seems that 343 is the max I can get with Prime being stable for 14 min on small FFT and 19 min on large FFT.
On to the next step..

2. Max Chip capable - Set multiplier to it's maxium -Set vcore to 1.6 -1.65 for 130nm chips, 1.50-1.55 for 90nm chips -Set mem to SPD and 100, this will take memory out of equation -starting with HTT 200 raise in about 5Mhz increments up to boards max found earlier or until you start failing PRIME95 which will probably happen first..only give it 5 minutes max, that's good enough for now. -At the point it starts failing within that 5 min time period, back down 5%, (CPU MHZ * 0.95), thats your max CPU speed, now test prime again at 95% for 12 hour for stable.

Do I really have to up the voltage right now? Isn't it better to only raise it if you absolutely have to?

 

[ITPaladin]

It would not boot with RAM at 200 Mhz. I had to set SPD instead. I have HT Freq at 4x, multi at 10, and raising FSB from 200 now.

 

[GuitarDaddy]

To test max CPU you will need to up the voltage, up to 1.55 is safe IMO

And for this step I would set the HT frequency to 3x, And set the memory to DDR200 and try with both the 9x and 10x cpu multi. If the best you can get with the 10x multi is say 250x10=2.5ghz, you may be able to get 288x9=2.6ghz, the point is try with both.

 

[ITPaladin]

So far I can't seem to boot past 216 Mhz, 200 RAM, x10 multi, and default voltage, so I guess I will up the volts then.

 

[ITPaladin]

So far this test is going better. I am up to 240 Mhz, 1.5v, 4x HT, 200 Mhz RAM.
I am thinking my "relaxed latency" Patriot RAM will be a problem. It runs at 3-3-3-8.

 

[ITPaladin]

250 Mhz, 11 minutes Prime95 small FFT stable so far.

I guess I move the HT down to x3 now.

 

[ITPaladin]

Finally reached the point where I got an error within the first 5 minutes: 272 Mhz while running large FFT.

I guess that means around 258 Mhz FSB x 10 multi @ x3 HT is my max CPU.

 

[ITPaladin]

what do I do now for memory step?

3. Memory MAX It depends what you want and type of mem you chose, LL or Bandwidth but must keep 1T (command rate) because A64 suffers big time with 2T. -For high bandwidth set mem setting to 200 and 2.5-4-3-7 1 T and give it boards max volts, or for LL set mem setting to 200 and 2-2-2-7 1 T and give it boards max volts. (up to 2.9Vdimm is safe with all ram) ( Caution DFI/ABIT users -- do not exceed 3.0V unless you know what you are doing!!!) -Set CPUs multi to 6-7, again to take it out of equation. -Raise HTT up to boards max or until you start failing memtest86 test 5 and 6 http://www.memtest86.com/ -When you start failing memtest86 test 5 and 6, back down 5%, (HTT * 0.95), thats your max MEM speed.

I have the Patriot eased latency 2 GB kit (pdf file link).
I know nothing about 'timings'.

 

[djdrastic]

Here is one of my favorite links

This guy went ot a lot of trouble

OverClockersonline

 

[ITPaladin]

thanks. Too much to read before bed.
My Patriot RAM will probably limit me. It runs normally at 3-3-3-8.
Time for bed.