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Help OC'ing my system...

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Dragon94375

Registered
Joined
Jul 19, 2005
Help OC'ing my system...7/23 still failing prime

System in signature...I've got the cpu and htt up and running where I am stable into windows...haven't tried stress testing it yet...

I need help with the memory portion...I'm rather confused between dividers and such. Supposedly my memory will go 2-3-2-5 (which is not set in bios yet) so any help on this would be apprecaited.

Here is the link to my CPUz thingy...
http://valid.x86-secret.com/show_oc.php?id=28256

Thanks guys..
D
 
Last edited:
Ok, so then you found a good spot for your CPU.

Now try going back to stock and running 1:1, with no divider. See how high your memory can go, then set the divider based on that.
 
Yeah...well that's my problem...I'm a total noob at this. I've never OC'd before! LOL I'm all confused on the dividers and such, what they are, and what to do. Here's a newer read from CPUz because I went and put the memory at 2-3-2-5 @ 1T

http://valid.x86-secret.com/show_oc.php?id=28258

And here is what is in my bios as far as the memory is concerned

DRAM Configuration:

Timing Mode - Manual
Memclock Index Value (mhz) - 266
CAS# Latency (Tcl) - 2
Min RAS# Active Time (Tras) - 5T
RAS# to CAS# Delay (Trcd) - 3T
Row Precharge Time (Trp) - 2T
Row Cycle Time (Trc) - 22T
Row Refresh Cycle Time (Trfc) - 24T
Read-to-write Time (Trwt) - 6T
Write Recovery Time (Twr) - 2T
1T/2T Memory Timing - 1T
S/W DRAM Over 4G Remapping - Enabled
H/W DRAM Over 4G Remapping - Enabled

I tabbed over to my jumperless settings and my DDR Volts is on Auto but it does have a range from 2.6 - 3.0 volts. I've heard that upto 2.8 or 2.9 is safe with this memory. OCZ themselves states 2.8 is still under warranty.
 
:welcome: Dragon.

The frequency of the RAM in an A64 system is always set by divding the CPU frequency by an integer. Changing the memory divider allows you to change that integer. Unfortunately, the BIOS settings for this are not as straightforward as they could be. However, it's not that hard once you realize what they're doing. For a detailed explanation, go to this thread
http://www.ocforums.com/showthread.php?t=306418
and scroll down to
"Overclocking Technique"

I see on your CPU-Z results, that you've already managed to set a divider (but then, maybe your BIOS has some sort of automatic overclockign utility that did that for you). If the link above doesn't help, please post a specific question :)
 
Otter said:
:welcome: Dragon.

The frequency of the RAM in an A64 system is always set by divding the CPU frequency by an integer. Changing the memory divider allows you to change that integer. Unfortunately, the BIOS settings for this are not as straightforward as they could be. However, it's not that hard once you realize what they're doing. For a detailed explanation, go to this thread
http://www.ocforums.com/showthread.php?t=306418
and scroll down to
"Overclocking Technique"

I see on your CPU-Z results, that you've already managed to set a divider (but then, maybe your BIOS has some sort of automatic overclockign utility that did that for you). If the link above doesn't help, please post a specific question :)

I'm at work right now but I took a quick look at what you linked me to. I'm printing it as I'm typing...should help some. How can you tell I have a divider set...and where is it at on that report?
 
It's not on the CPU-Z report, but your memory frequency was less than 200MHz while your CPU was overclocked quite a bit. No way to do that without a divider.

I'm not familiar with your board, but in your BIOS the dividers will be expressed in terms of maximum memory frequencies -- 200MHz, 183MHz, 166MHz etc. If you keep your HTT base frequency set to 200MHz, your RAM will be at the "maximum" frequency or less. If you raise the base, that proportionately OC's both the CPU and the memory. Hence, these are only the maximum frequencies if you don't overclock.

To find the actual divider, just multiply the CPU multiplier by 200, divide by the max memory frequency, and round up.
Divider = ceiling(CPU_mult * 200MHz / Max_Memory_Freq)
("Ceiling" in the formula above is the round up function rather than a variable.)

When you get home, read the sticky and play around with the BIOS a bit. I think you'll see how it works. If not, you know where to ask your questions. :)
 
I mean the "maximum memory frequency" setting in the BIOS. 200MHz, 183MHz, 166MHz, and 150MHz are fairly common values. These are sometimes also expressed as ratios, 1:1, 11:12 etc, but (as far as I can tell) calculating from the frequencies more accurately duplicates the calculations made by the BIOS.
 
Ok. Right now I am using pc3200. I have to set the DRAM clock to 333 in order to overclock the cpu. I have ordered 1x512mb pc4000 ballistix. Will I be able to set the DRAM clock to 400 which is the maximum memroy frequency in bios?
 
To run with the 200MHz/DDR400MHz/"1:1" setting, your new RAM would have to run at 278MHz, the same frequency as your HTT base. The module you're getting is rated for 250MHz. I'm not sure if it will do 278 or not.

From your sig it looks like you're using the the 9x multiplier. DDR333 actually uses a RAM clock of 166MHz. Hence, your current memory divider is
9*200/166=10.8 rounded up to 11.
Which means your PC3200 is doing 2502MHz/11, or 227MHz -- a 13% overclock beyond the stock 200MHz.

Two things to consider:

For an A64, tight timings are as or more important than a high RAM clock, and the very best RAM gives only modest gains compared to the better cheap stuff. If you can tighten the timings on the PC3200 you have, it might come close to the new Ballistix in real-world performance.

If you use more than 512MB of RAM, the slowest, loosest 1GB setup you can get will run circles around best 512MB system. That's because once you run out of physical RAM, the windows starts swapping to disk, and the ..... d...i...s...k ..... i..s ....v...e....r...y ..... s...l.....o....w
compared to any RAM. If you are dipping into the pagefile, send that expensive Ballistix back and get a mate for your corsair, or get two mid-priced 512MB sticks.
 
Otter...

Ok maybe I'm retarded or just Memory OC'ing illeterate but...how do I know I'm running the right "Memclock Index Value" as is posted in my bios being 266...for the memory I have? I don't understand why this is so confusing for me. I got the CPU thing right out the box...yeah sure it's easy but I've never OC'd anything before. And when you do your math equasion...as you did in the one for avalance...when you came up with the 10.8 (rounded up to 11) what the hell is that for? How does that tell you what divider you need?
 
Maybe I'm asking the wrong question...

Should I be asking where do you believe I should have my "Memclock Index Value" at or around?
 
Ok lastnight I toyed with it a bit but...this is retarded...wtf am I doing wrong??? Now I'm failing prime on ONE core but not the other!!! I am going to test Prime95 at stock speeds when I get home but...I went ahead and did prime as follows...

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.

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

I did set the affinity to one core each prime (running 2 primes at the same time). I had multiple settings that I ran...first of which was 256x11, then 250x11, then 245x11, then 240x11.5, then 235x11.5, and now 230x12. Yet it STILL fails!!! What am I doing wrong here folks? Could my processor be bad? Could it be my M/B? I am not sure on that one since I've seen others with the 4800+ and the 4400+ running upwards of 2750 and into mid 2800's. I'm not looking to make this thing faster then all hell but I would like to at least get 2.7 out of it...I'd LOVE 2.8 and I'd call it a day! Can ANYONE with the same MB as me and something close to the same memory and/or CPU... could you give some guidance?

Oh I forgot to mention...I did find that the top of my limit on mhz for the HTT (fsb) was 257...so I'm WAY under that right now
 
Dragon41673 said:
Ok lastnight I toyed with it a bit but...this is retarded...wtf am I doing wrong??? Now I'm failing prime on ONE core but not the other!!! I am going to test Prime95 at stock speeds when I get home but...I went ahead and did prime as follows...

Oh I forgot to mention...I did find that the top of my limit on mhz for the HTT (fsb) was 257...so I'm WAY under that right now
What is your LDT multiplier? HTTxLDT should not go over 1000.

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

-set LDT to 2, this will take the HT bus out of the 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.


BTW, HTT is just a base frequency used to set other frequencies. It isn't the FSB or any sort of bus at all. No data is transmitted over it. People like to call HTT the front side bus because when overclocking it's raised in about the same way the FSB would be on a CPU that had a FSB. But the A64 does not have a FSB.
 
Dragon41673 said:
Maybe I'm asking the wrong question...

Should I be asking where do you believe I should have my "Memclock Index Value" at or around?
First find out how fast your RAM can go.

I'm hoping that yoru board is actually capable of HTT frequencies beyond 257 once you lower the LDT so that the HT Bus isn't clocked over 1000MHz. If you get to a RAM clock of 257MHz with the method below, then your RAM is being limited by your motherboard. It might be possible to clock the memory higher even with the HTT limitation, but let's jump off that bridge when we come to it. Most PC3200 won't go that high anyway.

-Set your CPU mult to 5 or 6.
-Set LDT to 3.
-Set the "Memclock Index Value" to 400MHz. At this setting, your memory clock is equal to the HTT frequency.
-Set HTT to 200.
-Raise HTT in 5MHz increments until you get errors, then back off a bit to your maximum stable memory OC.

Once you know your maximum stable CPU and memory overclocks, the next step is to find the divider that gets you closest to your max memory frequency without going over.

Post
your max HTT with LDT set to 2 or 3,
your max CPU clock,
your max RAM clock,
and the available "Memory Index Value" settings in your BIOS,
and I'll walk you through the divider selection. :)
 
Thanks Otter...I had a little help from another member in another forum that has the same board I have and the same CPU...just different memory. So far so good...but I might be back for some memory help if you don't mind.

To those that did post and tried to help...thank you. After playing with this for a while and with some explanations you've given me...I'm starting to get this! LOL
 
Ok...lastnight I did what another member from another forum said to do. I retested everything using the following method:

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.

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.

352 was the top mhz while using a 3x LDT (booting into windows)
350 is where the memory would pass memtest
When I went to dual prime95 the cpu at that speed...IT PASSED as of this morning when I woke up. So I go into bios to play with the memory, and I realize something...I'M A DORK!!! I left the damn multi on 6x! LOL

Now I went and did prime at 9x multi. Wouldn't hold into boot. So I backed down to 350, then 345, and so on by -5 till I got into windows somewhere around 330 or 335. Then I tried to dual prime95 it. Wouldn't hold for more then 10-15 seconds. So I backed down by -5 each time and right now I'm at 300 and it's been dual prim95 stable for about an hour so far. That's right where another person told me his was at (same board & cpu, different memory)...so it looks like the ASUS A8N-SLI Premium has some sort of limit here. I've loved ASUS boards for years...but now on my very first attempt to OC...I'm wondering why I didn't go with a DFI! LOL I don't want tremendous speed...but I would have loved 2.8 out of it! Oh well...I'll play with what I have till I have extra cash and I might go DFI someday...

I'll report back and let everyone know what went on.
 
Ok...I know I just posted the previous one but prime was running for a while. I just got back to my computer and the prime failed after 35 minutes on one core. I did a stock prime and it did pass yesterday so I know it's not a bad core.

Here is what I have it at...
fsb = 300
cpu multiplier = 9
HTT multipler = 3
cpu voltage = 1.53
pci = 33

Any idea what's going on?
 
Well, it's possible that's as far as you can go with that Vcore and cooling.

Some boards get cranky with high HTT. Try 270x10 or 225x12.
 
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