Overclocking my Athlon 64 3000+

[chimpy]

I managed to get my A64 3000+ to here: http://img523.imageshack.us/img523/406/cpu20250xr.png

I did this by increasing the HTT to 225Mhz (as you can see) and upping the memory voltage to 2.60V. My PC won't get very far if I up the HTT to anything past 225, even if I crank the memory voltage up to 2.80V.

So, what should I do next? I've heard of the phrase 'using a divider to overcome the limitations of Value RAM', or something like that. I have Value RAM, so is that what I need to do? If so, how? Or do I have to do something involving upping the CPU VID? Thanks for any help, specs in sig.

 

[m1ldslide1]

I think you aren't getting many responses because there is so much documentation around the web about how to do this. But I personally had trouble understanding the mem divider until somebody ponied up the explanation to my direct question in the forums here, so I'll give it a shot for you:

Using a mem divider is telling your BIOS that you want to run your DDR400 memory at DDR333, for instance. Think ratios: 333/400 = .8325, which is what people mean when they say a 5:4 divider (4/5 = .8). So you take your number, which is .8325, and you multiply that by your external clock (or what you call HTT). So if you take 220Mhz external clock, x10 for your CPU multi you get 2.2Ghz. Now if you set your divider at 5:4, you can up your memory speed to 264Mhz since 264 * .8325 = 220. But instead of 220 x 10 = 2.2ghz you're now staring down 264 x 10 = 2.64ghz.

I can't get above 230 at 1:1 with my mushkin RAM, but with the divider I get stable at 280Mhz (280 x .8325 = 233). I drop my multi to x10 and I have 2.8Ghz, which is 600Mhz over stock speed. I'm not saying you'll necessarily get that high, but you should add 300mhz without too much grief.

Two caveats: Make sure the HTT multiplier is 4 or less. HTT x External clock = less than 1000Mhz. I have my HTT turned to 3x, which 3x280Mhz = 840, which is a little low but about right for my settings.

Secondly, you'll likely need to loosen your memory timings. Stock for my RAM is 2-2-2-5, but I have it at 3-4-4-10 @1T right now to achieve stability. It took me a lot of tweaking to find the right numbers for my system.

What's funny is that after typing this out I realize how much more there really is to explain about this process, such as voltages and cooling and all that jazz. I'd say that if you really want to learn to OC you should just do like you're doing and start messing with it. It's not terribly likely that you'll break something, and you should read everything online you can get your hands on about how to OC the right way. And then read it again. Then wait three weeks and read it again. Even once you get a good OC you'll keep learning ways to get just a little more out of it...

 

[chimpy]

Wow, thanks so much for that post. Sorry I didn't get back to you earlier. Although it does sound pretty complicated right now, I do understand a lot of it, and can see myself understanding it all soon enough.

One question though - what do you mean by ''Make sure the HTT multiplier is 4 or less.''? The stock multiplier is 9x, and if I drop it to 4x, it will more than half my speeds, right? Sooo I don't get why I should do it, lol. Does it mean I would be able to get a much higher HTT or something? Thanks once again.

 

[m1ldslide1]

Your HTT multiplier is different than your CPU multiplier. (Your CPU multiplier should probably be either 8x or 9x)

I forget the full explanation of HTT about five minutes after I read it, but suffice to say it's kind of like a front side bus but better. AMD has on-die memory controllers that allow it to eliminate the FSB and replace it with a HTT. Know how your motherboard says 1000Mhz FSB on newegg? That's actually the HTT, which is 200Mhz x 5, which should be the stock HTT multiplier.

The problem is that every motherboard has a different BIOS and can use some of these terms interchangeably. It took me a good while to figure out what meant what on my asus board. On my motherboard I only have one setting that says "HTT", and that's the multiplier field. It kinda sounds like your MSI board refers to the RAM speed as HTT, so it's up to you to find the right field to modify. I can tell you that the HTT multi field should have the options "5x,4x,3x,2x,1x,AUTO" or something very similar.

Again, not to be confused with your CPU multiplier... If you set the CPU multi to 3x with 225Mhz memory you'll end up with 775Mhz processor speed, which you would not be happy with :laugh:

 

[aberdeen5]

Goodluck with your overclock. Looks like we have the same CPU, same venice even(E3), and motherboard. Make sure you post your results!

 

[chimpy]

Thanks - yeah, I thought you were talking about the CPU multiplier, that's why I was a little O_O and didn't understand what you meant.

OK, so I set the HTT multiplier to 3. My HTT is at 225 right now, with my RAM at 166. Voltages have been left unchanged. I'm gonna try and up the HTT again next (I tried it before to no avail, even after upping the CPU VID). Now I have set the CPU multiplier down though, it may help me get a higher HTT. I'll report back after wards (maybe tomorrow). Thanks.

 

[KoolDrew]

Find the max for your HTT first. Then CPU, then RAM.

http://forums.anandtech.com/messageview.aspx?catid=28&threadid=1497607

 

[m1ldslide1]

Originally posted by: KoolDrew
Find the max for your HTT first. Then CPU, then RAM.

http://forums.anandtech.com/messageview.aspx?catid=28&threadid=1497607

This quick and dirty OC guide is pretty sweet - I've probably read it 20 times. I probably would've only read it 5 times, but I find the article assumes that you already know how to OC and so doesn't really explain what a lot of things are or how they work together.

The first paragraph about finding your max HTT doesn't make any sense to me, and that may be because I've only overclocked one MoBo. I understand what the HTT is and what range is acceptable, but I have no setting for "HTT Mhz" in my mobo. I only have a "HTT multiplier", which I had understood as what you multiply your memory speed by to get your HTT. In my case, 280Mhz memory x 3 HTT multi = 840. In my experience, setting my HTT multiplier to 2x gets me the EXACT system performance as setting it to 5x. I read that this is because the HTT bandwidth isn't being fully used by any present hardware and so your only concern for HTT is that it doesn't overshoot 1000mhz.

This is of course different for intel boards with FSB...

 

[KoolDrew]

The HT is determined by the HTT multiplier * HTT. The HTT is what you are refering to as for memory.

 

[chimpy]

OK, my PC won't boot if I up the HTT past 255, and it crashed at 255 after 5 mins or so (only had Firefox running). So, I'm running it at 250 HTT now, with 3x HTT multi, and 166RAM. Voltages are unchanged. Should I try upping the voltage to get a higher HTT? Or lowering the RAM? Or is there some other setting that I'm unaware of?

 

[KoolDrew]

Read the guide I linked to. You really need to find the max for each component first. It will make everything MUCH easier. Especially since after you found your max figured you can enter them here and it will give you the best options.

Just upping the HTT and then trying to figure out whether the CPU, board or RAM is holding you back is definitely not the way to go. By finding the max of each component you know what you have to work with.

 

[KoolDrew]

Also, with a 255 HTT and a 166MHz divider your RAM would be running at around 208Mhz (above stock). Your RAM may not be able to run this. This is why you need to find the max for your RAM along with the max for both the CPU and HTT. Then you can put it all together.

 

[m1ldslide1]

You've loosened your memory latency timings right?

Also, try running 250 HTT at 333 memory, which results in 250 * (333/400) = 206, which combined with a x9 multiplier is a very slight overclock (54Mhz). If that fails, then there's something else we're missing here...

Your HTT multiplier looks good.

As far as voltage, I've used the guidance in the A64 overclocking guide that kooldrew posted. I found that my particular memory responds best between 2.6-2.75 vdimm, and absolutely sucks at 2.85 and above. My CPU is fine at 1.45 vcore - I could probably even go a little lower.

 

[m1ldslide1]

Originally posted by: KoolDrew
Also, with a 255 HTT and a 166MHz divider your RAM would be running at around 208Mhz (above stock). Your RAM may not be able to run this. This is why you need to find the max for your RAM along with the max for both the CPU and HTT. Then you can put it all together.

Yeah, what he said.

 

[chimpy]

OK, thank you KoolDrew - I'll check the guide out tomorrow. I'm off to bed now though, so I'll report back sometime tomorrow. Thank you both so much.

aberdeen5 - sorry I didn't reply to your post, I didn't see it before now. Wow, nice overclock - I always thought this mobo was regarded as a not-so-good overclocker. Nice to see you got it to 2.7, I hope I can get mine cloce to that, though I doubt I will.