Overclocking my X2 3800

Accipiter22

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Feb 11, 2005
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I used to have a 3500+ and all I want out of the X2 3800 is to run at the same speed as my old 3500.

So I set the FSB to 220 on the 3800 (the multiplier is 10) so now the core speed is 2200. Is there anything I should do with the memory frequency??? I go into CPU-Z and under the Memory tab, it says the frequency is currently 220 Mhz....is that fine?Also it's command rate is 2T, should I change that to 1T?

edit: I"m using an ASUS A8V-Deluxe, and my ram is Corsair Value Ram PC3200 variety, with stock timings of 2.5 3 3 8

I really dont' get ANYTHING about overclocking or underclocking RAM at all...like how is that supposed to work?? You overclock your processor and then slow down your ram to make your ram go faster or something?? I'm baffled. I tried following the quick & dirty guide that's sticked at the top, and I'm fine till I get to the memory testing part, and consolidation part.
 

BlueWeasel

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Jun 2, 2000
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Currently, you have a 1:1 divider for the RAM, which means it's going to run at the same speed as your FSB/HTT. That's great, if your PC3200 is stable at 220Mhz. If not, then you've got several options.....lower the timings, increase the RAM voltage, or both. If doing those does help stability, then you'll need to use a divider to run the RAM at a lower frequency.

Once you've isolated the maximum FSB/HTT of each part (CPU/RAM/MB), then it's just a matter of consolidating each value to give you the maximum highest clock speed.

If you're happy with 220x10, then it's pretty much a given your CPU and MB won't have a problem. Then, it's just a matter of getting your memory stable. Given a slight bump in voltage and/or some timing tweaks, your PC3200 probably will be perfectly stable at that speed.

Why not push it further? You've got the hardware to hit 2.4-2.5Ghz or higher. :)
 

cubeless

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Sep 17, 2001
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u would probably be better off
1) setting the memory to 166 (first divider below 1:1)
2) the 'fsb' to 250
3) the voltage to 1.4

this will put your memory at 200... 220 on valuram is kinda pushing it, in my experience...

i just installed one of the latest newegg 3800's and the above settings are nice and stable (2.5ghz)... the chip wants a bit more juice to go any higher and gets a lot hotter...
 

Frintin

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Oct 3, 2002
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2.4 to 2.5 is a nice overclock right there on that chip!

If you can get the HTT to 240MHz then when the memory clock is set to the proper divider for DDR333 operation the memory actually runs at 400MHz. Lock down the PCI and PCI-E bus speeds using the motherboard's BIOS, and you're running virtually everything but the CPU and HyperTransport link at stock speeds.
 

Boyo

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Feb 23, 2006
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Originally posted by: Frintin
2.4 to 2.5 is a nice overclock right there on that chip!

If you can get the HTT to 240MHz then when the memory clock is set to the proper divider for DDR333 operation the memory actually runs at 400MHz. Lock down the PCI and PCI-E bus speeds using the motherboard's BIOS, and you're running virtually everything but the CPU and HyperTransport link at stock speeds.

:thumbsup: What he said makes perfect sense. Try that out....
 

Accipiter22

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Feb 11, 2005
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ooh yeah, those lock things...I have a setting for it in the ASUS bios...I have it set to automatic right now, is that ok?
 

cubeless

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Sep 17, 2001
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no, probably... if u can set it to lock the pcie to 100, the pci to 33... sometimes the auto makes a bad call on the value...
 

Accipiter22

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Feb 11, 2005
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Originally posted by: cubeless
no, probably... if u can set it to lock the pcie to 100, the pci to 33... sometimes the auto makes a bad call on the value...

this applies even if I have an AGP mobo right?
 
Dec 8, 2004
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Yes, that would be for an AGP mobo.

I like using the 166 divider and setting the FSB to 250 myself. If you want the CPU to run a little cooler choose a CPU multiplier of 9 for 2250mhz.
 

Accipiter22

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Feb 11, 2005
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OK, here's what I did...I left the mem thing on auto, since I remember that it'll divide by itself sometimes. Here's a screen shot from CPU-Z: CPU-Z


Should I change anything?

Also I set the AGP/PCI lock thing to 66.66 / 33.33 I believe, is this correct?

At 2.40 I'm still idling at 39 celsius, the same as I was at 2.0
 

BlueWeasel

Lifer
Jun 2, 2000
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Yep, it looks fine. The AGP and PCI lock settings are correct.

The RAM isn't overclocked based on that screenshot, so the 166 divider must have automatically kicked in. You could probably gain a slight boost by overclocking the RAM and therefore increase the bandwidth. But, the bandwidth boost from RAM running at 220Mhz vs 200Mhz is neglegible, and the key to remember with the A64/X2 chips is clock speed is always king.
 
Dec 8, 2004
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That CPU-Z link is bad, but it sounds like you did good. The AGP/PCI setting is correct. If you are stable, go have some fun and forget about it. :)
 

cubeless

Diamond Member
Sep 17, 2001
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i'm just rooting u along to try 250 fsb... if your valuram ran 220 before it ought to be able to run up to 250 fsb at the 166 divider...

if u have just 1 or 2 sticks of memory u can try going 1t... just have all of your bios settings written down, since u may end up clearing cmos if it hangs up... my msi k8n can recover from any oc booboo but trying 1t when it won't go (since i have 4 sticks of memory...

and my x2 3800 is now at 2.55... buwahahaha... catch me if u can...
 

bigpow

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Dec 10, 2000
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try my setting:
CPU: 10x 250, 1.45V (or 10x 270, 1.5V)
RAM: adjust to your spec like 166/200*260=215, (I've DDR500 so I'm running 1:1), max volt for your RAM (I'm at 2.7V)
Always try to run at 1T, about 10% difference there - everything could be at auto (SPD)

Don't forget HTT multi = 4x or 3x (not 5x)
& disable all spread spectrum

easiest O/C for 3800+ is 10x250, RAM at 166/200 (if using value RAM), HTT 4x
 

Accipiter22

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Feb 11, 2005
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Originally posted by: cubeless
i'm just rooting u along to try 250 fsb... if your valuram ran 220 before it ought to be able to run up to 250 fsb at the 166 divider...

if u have just 1 or 2 sticks of memory u can try going 1t... just have all of your bios settings written down, since u may end up clearing cmos if it hangs up... my msi k8n can recover from any oc booboo but trying 1t when it won't go (since i have 4 sticks of memory...

and my x2 3800 is now at 2.55... buwahahaha... catch me if u can...

the race is on!
 

Accipiter22

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Feb 11, 2005
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Originally posted by: bigpow
try my setting:
CPU: 10x 250, 1.45V (or 10x 270, 1.5V)
RAM: adjust to your spec like 166/200*260=215, (I've DDR500 so I'm running 1:1), max volt for your RAM (I'm at 2.7V)
Always try to run at 1T, about 10% difference there - everything could be at auto (SPD)

Don't forget HTT multi = 4x or 3x (not 5x)
& disable all spread spectrum

easiest O/C for 3800+ is 10x250, RAM at 166/200 (if using value RAM), HTT 4x


what's the HTT multi?? and spread spectrum?
 

Accipiter22

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Feb 11, 2005
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Honestly....My games are going slow while overclocked...like civ 4 draaaaaaaaaags, it's roughly 1/4 as fast as it was before I overclocked. I think it needs the processor to be at stock speeds to run well, it runs like ****** otherwise. Same with limewire and every other program I run. They all run in the mud overclocked. blech
 

bigpow

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Dec 10, 2000
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if your pc run slower when o/c-ed, try running prime95, memtest or other stability test - it's probably crashing left & right
since it's a dual core, you need to run 2 instances of the stability test if it doesn't support dual threading
pay attention, you could also run into data corruption if it's unstable
you should run these tests for 24-48hours non-stop, without it crashing or failing - before you use that setup


it SHOULD NOT be slower, it should be like replacing your CPU with a faster one - without paying Xtra $$$ (well, maybe pay a little $ for HSF, good pair of RAM & o/c friendly mobo)
 

myocardia

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Jun 21, 2003
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Yes, you want your Value RAM running slower than the processor's HTT/FSB. Slower= more stable.
 

cubeless

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Sep 17, 2001
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check your actual speed... mem set to auto might kill u... i only have had a slowdown when oc'ing a vid card...

use cpu-z and a64tweaker to see what's actually going on once the pc is booted...

i just broke 5000 in 3dmk06 and 10000 in 3dmk05... just had to push my vid card a little bit more (quit being lazy and using ati ccc and hand oc'd...)...

it's a bit of work to get things sorted out, but what else is there to do on a friday nite???