Could someone please help me overclock my new P4PE?

[Rick67]

I'm running a P4 2.53GHz with one 512MB stick of Corsair CMX512-3200C2 (CAS Latency 2-3-3-6-T1).

I'm not really interested in overclocking the CPU at this time. I realize the approved memory speed for this mobo is PC2700 (333MHz). What I'd like to do is run my memory at PC3200 (400MHz).

I'm new at this whole PC building thing and I'm not sure what changes I need to make in the BIOS to run the RAM at 400MHz. Could someone help me out with these settings? Also, what tests do I need to run after making these changes to insure my system is stable?

Thanks,

 

[buckchoi]

You wont reach DDR400 without pushing the FSB up since the board does not offer the dividers to run DDR400.
This mean you will o/c the CPU too....I dont think theres any other way round it.
Someone correct me if i'm wrong as i haven't used one of these boards yet

 

[Rick67]

OK, I was planning on overclocking my CPU anyway, so exactley what do I have to do? I'm really not sure how the CPU works with with the memory speeds so could someone please explain how this works? Thanks,

 

[First]

Originally posted by: Rick67
OK, I was planning on overclocking my CPU anyway, so exactley what do I have to do? I'm really not sure how the CPU works with with the memory speeds so could someone please explain how this works? Thanks,

It's simple; all you have to do is raise your FSB in the BIOS to 150MHz, and since memory frequency changes as the FSB changes (with the P4PE that is), there will be an option in the BIOS for DDR400 operation (at 133MHz FSB, you should have memory options for 266, 333, and 355MHz).

From there, your RAM will be running at 400MHz and your CPU will be running at a multiplier of 19 x 150MHz which = about 2.85GHZ core clock. ASUS nor Intel guarantees this sort of high frequency operation, but I encountered no issues whatsoever at even higher speeds than 150MHz FSB/400MHz mem in my testing. Just make sure to set your VDIMM (memory) to 2.6V.

 

[Rick67]

Evan,

I don't really understand the memory option of 266, 333, and 355. Which one of these do I use?

Thanks for all the info! I really appreciate it and it helps a lot!

 

[CrazySaint]

Originally posted by: Rick67
Evan,

I don't really understand the memory option of 266, 333, and 355. Which one of these do I use?

Thanks for all the info! I really appreciate it and it helps a lot!

Here ya go:

1) Increase vdimm to 2.6v
2) Set FSB at 150MHz (which will set your clockspeed at 2.85GHz)
3) Verify stability by running prime95 for a few hours with no errors.
4) If you get any errors, increase vcore one notch.
5) Repeat steps 3-4 until A) You get no errors or B) You've reached 1.6 vcore (as set in BIOS). Asus boards tend to overvolt so anything higher than 1.6vcore could damage your CPU.
6) Enable the 3:4 memory ratio. The 3:4 memory ratio causes your memory to run 33% faster than your FSB, so 150FSB with 3:4 mem ratio = 150 x 1.33 = 200 memory clock = DDR400.

I hope this helps some

 

[Rick67]

CrazySaint,

Thank you!! This is exactly the info I needed and it clears up some questions I had. One last thing, I'm at work so I can't look at my BIOS at the moment. However, I don't recall a 3:4 memory ratio setting in the BIOS. Is it listed as something other then 3:4 memory ratio?

Also, what about the 266, 333, 355 memory option? Still not sure what to do with this.

Thanks for all the help guys!!

 

[oldfart]

Also, what about the 266, 333, 355 memory option? Still not sure what to do with this.

This refers to mem speed @ 133 FSB.

FSB x 2 x mem ratio. The x 2 is for DDR

133 FSB x 2 x 1:1 = 266
133 FSB x 2 x 4:5 = 333
133 FSB x 2 x 3:4 = 355
150 FSB x 2 x 3:4 = 400

 

[Andi316]

What divider can I use, when my FSB is 166 MHz? Is there DDR400 still possible?

 

[oldfart]

166 FSB 1:1 = DDR333
166 FSB 4:5 = DDR416
166 FSB 3:4 = DDR444

DDR444 is pretty tough to do. DDR416 is very possible with good mem such as Corsair XMS3000/3200

 

[cmdrdredd]

why not back down to 166 to get more stable operating?

 

[Rick67]

What should my CAS Latency settings be?

I've got my memory running at 400MHz and my CPU is at 2.85GHz. I just tried running 3dmark2001se and it crashed/rebooted. What adjustments should I make?

Again, thanks for all the help guys!

 

[jpetermann]

What do you have the mem voltage set to? You should be able to run the tightest settings with that ram, so It should not be a problem. You can try and lower the settings a little, but I would up the voltage on the dimms and the cpu as well if you ahve not already.

PJ

 

[oldfart]

Try the ram at the slowest settings first: 2.5,3,3,7. If that is stable, try speeding it back up.

 

[Rick67]

Here's my settings:

CPU Speed: Manual
CPU Frequency Multiple: 19
CPU External Frequency: 150
Memory Frequency: 400
AGP/PCI Frequency: Manual
AGP/PCI Frequency (MHz): 66.66/33.33
CPU Vcore Setting: Manual
CPU Vcore: 1.525V
DDR Reference Voltage: 2.60V
AGP VDDQ Voltage: 1.5V

SDRAM Configuration: User Defined
SDRAM CAS Latency: 2T
SDRAM RAS to CAS Delay: 2T
SDRAM RAS Precharge Delay: 2T
SDRAM Active Precharge Delay: 5T
System Performance Mode: Optimal

I think Anandtech used CAS 2-2-2-5 in their review but I'm not sure on the other settings.

I just bumped up the Vcore from 1.50V to 1.525V and I almost made it through 3dmark2001se without it crashing. Notice I said almost. Should I up my Vcore another notch or up the DDR Reference Voltage to 2.70V or both? BTW, ASUS PC Probe is showing my Vcore as 1.60V. Or should I change some of my CAS settings?

Thanks,

 

[jpetermann]

Yes, take it up to 1.55. You are safe there. See if that helps any... I had an Gigabyte 8irxp that I had to have at 1.6 to get it all the through 3d mark and stable. I was running a 1.8a at 2.4.



PJ

 

[oldfart]

Here is the way I do it. CPU first, mem 2nd. If you dont do it that way you cant determine what is causing your instability.

Set your mem to 1:1 for now, slowest timings 2.5, 3, 3, 7. This way, you know your mem speed is not an issue.

Test your CPU overclock, increase Vcore until you are stable (no more than 1.7V ACTUAL) Asus boards usually overvolt. Yours looks to be no different. 1.525 = 1.6 actual. This is one reason they are "perceived" to be great overclockers. They have the Vcore juiced up so high, it's no wonder they overclock easily.

Once you have the CPU stable, work on the mem speed. Go back to 3:4 DDR400, slowest mem timings. If everything is stable, speed up the mem timings until you get stability issues, then back off.

 

[Rick67]

Ok, with same settings as above except I bumped up Vcore to 1.550V. I made it through 3dmark2001se but received an error in Prime95 after less then one minute.

oldfart,

Your method sounds like the best way to tackle this.

 

[oldfart]

Dont bother with 3DMark. Prime95 is the way to go. If you can run Prime95 overnight, you are in good shape.

 

[Rick67]

I've got my Vcore up to 1.555V (in BIOS) and I'm still getting an error in Prime95. How much further can I go with the Vcore before it gets dangerous? FYI, I'm using the Intel retail heatsink and fan.

I'm currently running my memory at the slowest settings as oldfart suggested.

Nevermind about the Vcore. Several people have already said not to go past 1.7 actual.

 

[Rick67]

Well, I ran Prime95 overnight with my vcore in the BIOS set at 1.625 and it errored a little over eight hours in. Should I bump it up to 1.650 or give up?

I noticed over at hothardware.com that during their recent review of the P4PE they said they cranked the Vcore up to a "modest 1.75"! Is this really modest? I've been told not to go over 1.7V.

 

[oldfart]

Prime95 is extremely sensitive to the slightest bit of instability. 8 Hrs is not "Prime95 perfect", but I'd say you should see no stability issues with that setup. I'd leave it for now. Start working on the memory @ DDR400, get that set. Another good test is Serious Sam either retail or demo. That game will crash for certain if something is not right. If you can get that to run for a couple hrs with no crashes, you are in good shape.

 

[Spicedaddy]

What are your CPU temps at idle and under load?


For the voltage, just install Asus Probe and check it in Windows. On Asus boards it'll be ~0.2 over what you set in the bios. Anything under 1.7V in Asus Probe is safe, so you can probably go up to 1.675 in the bios.