Stuck OCing AMD Athlon 64 3800+ (Venice)

[Jeepinator]

I have reached a barrier which I cannot pass. I can only get my CPU to run at 2.64 GHz (220 MHz x 12). CPU voltage is at 1.5v and memory is at a stock 2.6v. I have tried going up to 225 in 1 MHz increments, but it will not stay stable even if I increase the voltage to the CPU or RAM. Does anybody have any tips. I know the 3800+ is capable of almost 2.9 GHz. I would like to get it near that mark. I have PLENTY of cooling and power.

I have tried different multiplier combinations as well. I have tried nearly every combination of voltage, multiplier, and FSB clock I can think of.

 

[marginalclue]

can you get your cpu freq past 220 MHz with a smaller multiplier? just asking because if not, you definitely need to run your RAM on a divider, which you didn't mention among your specs. if so, it's still probably the ram. what mobo are you using?

 

[Jeepinator]

I'm running the DFI Lanparty RDX200 (has the Radeon Xpress 200 chipset). I can set a divider, but I'm not totally familiar with adjusting it. I set it from a 1/1 to a 9/10 so the memory would be 9 tenths as fast as the FSB. It still wouldn't let me go beyond 220. There is a setting that says "LDT/FSB Frequency Ratio" and has options 5x, 4x, 3x, 2x, and 1x. It is currently on 5x. This is my first real overclock so an explanation oh what to do would be helpful. 🙂

I'll try pushing it past 220 with a multiplier of 10 or so and see. If that doesn't work I'll try a divider.

Okay I changed the multiplier to x11 and the FSB to 240 mhz. I then changed the memory clock to 5/6 of the FSB (putting it back at stock 200 mhz). I had to change the LDT/FSB Ratio to x4 (I still don't know what this changes). I should be able to get it to boot at x5, but I did that to be safe as it seemed to be getting quite high above stock values. The computer is running prime95 and has gone a good hour with it. I just hope it can keep going.

 

[4745454b]

The LDT thing sets the speed of the hyper transport bus. This should always be set at whatever gets you close to 1000MHz. If your bus is set at 225, then it needs to be dropped to 4. (225 * 4 = 900, 225 * 5 = 1125, which is way to high...) I know some overclockers drop it to 3 right off the bat seeing as it doesn't effect performance very much, and you won't forget to change it later.

 

[Jeepinator]

ok so now its on 240x4 so its at 960. even at 245 it should be 980. So I won't notice any performance loss with it below 1000?

I have been able to run this sucessfully:

http://valid.x86-secret.com/show_oc?id=151484

 

[4745454b]

Right. If you should get your bus up to 270 or higher, you might need to drop it down to 3. (810 instead of 1080) 1GHz or slower, thats what I've read.

 

[Jeepinator]

Doh after 2 hours I got an error! 🙁

I raised the voltage, but then after like 3 minutes I got another error. Do you think its the memory? The memory is running below its normal clock though.

 

[4745454b]

I don't think it liked the voltage increase. How much did you raise it to? If you only went to 2.65/2.7, then try either cooling the memory, or taking it back down to 2.6. Seeing as you got an error, you'll need to take the bus speed down to 239 or 238 and see if the memory error happens again. Seeing as it didn't happen within 3 min, I'm guessing that its a heat problem. I would try cooling the memory with 240MHz bus speed, and 2.6V ram. It probably errored after two hours because it got to hot.

 

[GlacierFreeze]

Deffinitely try running a divider if you're not doing so already. I forget the ratios but try a 5:6 (or 6:5 whatever). It'll probably be displayed as default 200 in BIOS. You're gonna want to change to 166 or lower (depending how it displays in BIOS). HT speed shouldn't affect you unless you go, say, below 600 (from what I've heard back in the day).

I'd put money on it that your memory speed (being too high without divider) is holding you back. It was for me when I first started, then I found the option to change to 166 and worked like a charm.

 

[Jeepinator]

Yeah, I'm already running the 5/6 divider. That puts my memory speed at almost 200 mhz, which is its stock clock. I haven't adjusted the memory voltage yet, just the cpu voltage. I'll try upping it to 2.65 or maybe 2.7v

 

[bolt14]

This makes two of us. I can't get mine to go over 2.70 GHz with a 225 FSB on a 12x mult. on stock voltage. Even with a voltage increase, it simply refuses to run faster. The computer simply won't post.

 

[TheProfiler]

It's probably mobo. I clocked mine CPU from 2.0 to 2.4 and that's the top limit, although my memory, HTT and everything else should go even higher and CPU is capable fot double that clocking.
But my mobo simply wouldn't allow me any higher, contrary to all logic and sane reason.
I tried everything and everything again.
But it's great, because before I flashed BIOS I couldn't go over 2.15 GHZ.