Need help with Overclocking Athlon 64 X2 3800+ on GA-M56S-S3

[KingFatty]

If you are adventurous, also realize that the overall speed relies on the multiplier and the base CPU frequency. So that introduces options, because maybe your maximum total performance will arrive when you use a very high CPU Freq like you have, with a lower multiplier. Or, maybe you'll find the total speed to be higher if you use a lower CPU Freq but a higher multiplier. The only way to know is to try each one. But ultimately it won't be too big a difference.

Also you have to consider the memory speed. As your CPU Freq increases, you are more likely to need to decrease the memory multiplier to keep the memory stable. So, that will also be a factor. Let's say you end up with two settings that produce roughly the same overall speed (say, your computer can handle 200*12.5 or 218*11.5, which both give you roughly 2500). So your CPU will run about the same with either of those. But what about your memory? It might turn out that your memory can run at 218 without needing to decrease the multiplier, so it's overall faster to choose that combination. But, as your CPU Freq goes higher and higher, you end up needing to drop down the memory multiplier and then you may end up slower (or faster, depending on the actual numbers).

So in the end, it's really good to keep a spreadsheet with the settings and also a 'notes' section where you enter your comments about instability. That way you'll know which CPU Freq, cpu multiplier, and memory speed/ratio can be stable.

Also, when you fail a test, ideally you will know exactly what caused the failure (CPU or memory), because only one setting will be increasing at a time. If you simply increase CPU freq without concern of your memory settings, then you may hit instability because of the memory and not the CPU (or vice versa). So try to make changes in a way that isolate only one variable, so when instability arrives, you know that's the particular thing you are adjusting.

 

[nwo]

but CPU Freq from mid 2-forties to 254 were always 1 lower in OS than in BIOS, 248 was 247, 250 was 249 etc. Only Sandra got it always right. Now it's OK everywhere.

Don't worry, that's perfectly normal.

when I set the CPU Freq to 258 as it is set right now with all the remaining values unchanged (set as the above) then Prime95 running in Blend flunks me after 6 min

What is the CPU voltage? Have you tried increasing it to see if it will give you stability at those speeds?

 

[kedolf]

you are more likely to need to decrease the memory multiplier to keep the memory stable.[...] (say, your computer can handle 200*12.5 or 218*11.5, which both give you roughly 2500). [...] But, as your CPU Freq goes higher and higher, you end up needing to drop down the memory multiplier and then you may end up slower (or faster, depending on the actual numbers).

Hi again and thanks,
sorry for a newbie question but how do I change the memory multiplier? Is it an option in BIOS or is it determined and arrived at by changing some other coefficients? And in the example you gave what is 200* or 218* value in "200*12.5 or 218*11.5" and where do I set such values?

If you are adventurous

My Exes kept telling me that...

 

[kedolf]

What is the CPU voltage? Have you tried increasing it to see if it will give you stability at those speeds?

Hi again and thanks too,
CPU voltage is still one notch higher than stock - CPU Voltage Control 1.375V. I have not tried increasing it yet on my present settings. I sort of hoped to keep it as low as possible for as long as possible to have some more leeway later on - what a dumb thing to hope for on stock cooling...

 

[nwo]

AMD's stock coolers were actually pretty decent back in A64 x2 days. I think you will be fine if you push it to 1.4v

 

[KingFatty]

It depends on your motherboard, but usually you will choose a memory speed. This is misleading, because really the motherboard is not setting the ultimate memory speed as suggested. Instead, it's taking the default base cpu frequency, and multiplying it by some multiplier, to arrive at the stated resultant speed. So when you change the base CPU frequency, the memory speed you select in BIOS becomes facially incorrect. But, it tells you what the multiplier is. So you can work backwards, by determining what the memory multiplier is based on the listed spec and knowing the default base cpu frequency, and then correct for your adjusted number.

The * (asterisk) typically represents multiplication. So it's just the product of the two numbers on either side of the asterisk; 200*12.5 = 200x12.5 = 2500

 

[kedolf]

@KingFatty & all

The * (asterisk) typically represents multiplication.

Hi there and thanks again,
I have met few asterisks in my life before so I've got a feeling I know what they typically represent. But seriously what I meant is where did this number ("200", "218") come from, what does it represent: Memory speed? FSB? Something else? I guess the "12.5" is the CPU Multi - in my case x10 is max or rather was because I lowered it to 9.5, FSB - 278 MHz and here is what I've got so far:
(Sandra Overclocking report)

CPU Type DualCore AMD Athlon 64 X2 5000+
[...]
CPUID CPU Name AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ CPUID Revision 00040FB2h
CPU Speed:
CPU Clock 2645.9 MHz (original: 2000 MHz, overclock: 32%) CPU Multiplier 9.5x
CPU FSB 278.5 MHz (original: 200 MHz, overclock: 39%)
HyperTransport Clock 835.5 MHz
Memory Bus 330.7 MHz
DRAM:FSB Ratio CPU/8
[...]
Memory Timings 5-5-5-18 (CL-RCD-RP-RAS)
Command Rate (CR) 1T
[...]
CPU Properties:
CPU Type DualCore AMD Athlon 64 X2, 2646 MHz (9.5 x 279) 5000+
[...]
Original Clock 2000 MHz
Min / Max CPU Multiplier 4x / 10x
[...]

Prime's done for 45 min, OKed, max temp 55C. IntelBurn did not freeze, OKed, at one instance temp jumped to 59C for a sec or so, average 56C and it looks like I'm one notch below 280 MHz at still 1.375V only. I know I owe you guys some beer, lots of it really. But I'm not done yet.