Quick overclock question for those in the know

vwgolfman

vwgolfman

vwgolfman

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I am new to overclocking and have a simple question if anybody can help.

I am using a Quad core 6600 CPU and wish to clock it to 3 GHz.
I am air-cooled but it is a decent Zalman jobby.
I also want to get the most out of my RAM.
I am using PC8500 (1066MHz) RAM.
I am using an ABit IX-38 Quad GT Motherboard.

In the BIOS the DEFAULTS are:
External Clock 272MHz
Multiplier X9
Estimated new CPU Clock 2448MHz
DRAM Speed (CPU : DRAM) DDR2-816

If I increase the External Clock to 334MHz this gives me an Estimated new CPU Clock of 3006MHz and a DRAM Speed (CPU : DRAM) of DDR2-1002.

Does this achieve what I am trying to do?

Do I need to make any changes in the "Voltages Control" part of my BIOS?

Thanks
 
Hi JackCarver.

Need I worry about anything else?
Voltages?

EDIT: Whoops I upped the FSB to 334 (and changed nothing else) and I got a BSOD!

Surely I shouldn't give up?
 
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FAO flibby or anybody else who can help......

What does flibby mean above when he talks about disabling Speedstep?

He also talks about making a very small increase in the vcore value to make it stable. What should this increase be typically?

Should I attempt to use ABit's uGuru application to do my overclocking or is it better done in the BIOS?

Many thanks for your help guys.
 
Hi flibby.

I had read about C1E/EIST in the interim but I still have many questions.

Would there be a chance to communicate via email with you?
Do you use SKYPE?

Anyway I have just written a piece and thought it might help others if I post it here.........

My hardware:

Abit iX38 Quad-GT
Intel Core 2 Quad-Core Q6600 G0
2GB (2x1GB) Corsair TwinX DDR2 XMS2 Dominator, PC2-8500 (1066)
Zalman CNPS9700-LED Super Aero Flower Cooler

I would like to Overclock my CPU to run at 3GHz and although it is air cooled I believe my cooler should get me there.
I would also like to run my RAM at 1066 but I am happy to play with that after I have a stable CPU at 3GHz.

There are several things which have been confusing me.

1) Speedfan and CoreTemp are giving me differing readings for the temps of the 4 cores. Why could this be?

2) I upped the clock to 333, leaving the multiplier at x9 to get my 3GHz without changing anything else. It wouldn't boot. Is this because I need to up some voltages?

3) You say it is better to make changes in the BIOS rather than using an Overclocking applications such as uGuru but due to some indifferences with the iX38 Quad-GT it is sometimes necessary to clear the CMOS after a crash has occured due to an overclock failing. Would it be possible to "try" thing in uGuru and if they work then make them permanent in the BIOS?

4) Am I correct in thinking that uGuru (which starts at bootup) "temporarily" applies the selected settings to the hardware? i.e. it applies any modifications to the standard BIOS settings each and every time it starts up?

5) If I select "Turbo mode" in uGuru it makes the following changes (from and to). Please can you explain them?......

ExtClk: 272 > 293
Target Voltage: 1.3 > 1.45 (CPU VID remains at 1.3_Auto)
CPU Offset: 0.000 > 0.150
CPU VTT: 1.00 > 1.27
MCH 1.25: 1.25 > 1.37
ICH 1.05: 1.05 > 1.12
ICHIO 1.5: 1.50 > 1.60

6) There appear to be so many modifications when selecting "Turbo mode". Would I be correct in thinking that all of these would need modifying in an attempt to get to 3GHz?

7) Which applications should I use to monitor my core temps and load my CPU to check it under load?

8) Once I am happy with my CPU at 3GHz would it be a simple task to get my RAM performing at 1066? How would this be achieved?

Many thanks for any help.
 
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It's very generous of you to spend all that time helping me (and others) flibby - cheers.

I shall do all you ask (and report back) straight after dinner which I am about to have :D

Give me an hour ;)

In the mean time can I just ask whether there IS a quad version of Prime95 or are we just talking about the latest version here?
 
Well I've not had much success :eek:

I modified the settings you suggested and rebooted (at this stage I hadn't upped the Clock to 334).

The machine started to boot but about 5 seconds into booting it rebooted, this time booting up into Windows.
I then rebooted and hit DELETE to go into the BIOS. All settings were back to their original settings.

How could this have happened?
 
I have some questions....

What is VDroop?
What is the CPU core voltage offset used for?
The "Target CPU Core Voltage" appears to be a combination of the CPU VID and the offset. What is this used for?

I have heard that the IX38 Quad GT is particularly good in the VDroop department but how do I "enable" this feature?

Thanks again. I am making some tests at present and shall report back.
 
Thanks for your info.
I am getting some results now.

I set the RAM timings manually as you suggested.

My CPU VID is 1.3V by the way.
I have disabled C1E and EIST but they didn't seem to affect the CPU VID anyway (monitored in CoreTemp). I was under the impression that with C1E and EIST enabled that the CPU VID would change when under load (Prime95) compared to idle but it didn't. Why is this?

Currently these are my settings....
Clock 320
Multiplier X9
CPU Clock is currently 2.885GHz
DRAM 1:1.25 (800MHz)

Core temps under load (Small FFTs) are 57, 48, 48, 57.

It appears to be perfectly stable.

I intend to up the External Clock to 333 next and leave the RAM divider as it is (that will give 833MHz RAM).
Let's see what happens (will report straight back)......

What should I do next if it is happy at 333?

PS all voltages are still at stock.

EDIT: BSOD just before reaching Windows!

Should I up the CPU VID one notch or more? One notch takes me to 1.3125V. I did this but still had a BSOD so I have taken it up 2 notches to 1.325V and now it boots.
 
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Sorry for the confusion.

I am at 333x9 with a 1.325V VCore.
However, although Prime95 ran OK when I ran 3dMark06 the first test bombed out.

I suspected RAM as this is now running at 833 at 1.8V.

For this reason I have taken the RAM back a notch on the divider and I am about to run 3dMark06 again.

On the Corsair website there is a .pdf for the RAM I have and it states:

SPD 5-5-5-18 @ 800MHz
5-5-5-15 @ 1066MHz 2.1V

Does this mean that SPD will not control timings above 800MHz?
i.e. I MUST set timings manually for >800MHz?

Do these figures also suggest that in order to go >800MHz I MUST increase DDR2 Voltage?
 
Complete update:

Now at 333 x 9 (3GHz) with NO increase in CPU Core (it is on 1.3V stock).
DDR2 divider at 1:1.2 (800MHz). Manually set timings as you suggested 5-5-5-18.
All other voltages etc are at stock.

All is stable with core temps of 59,49,49,59 under load (Prime95 small FFTs).

1) I cannot afford to have my machine crash on me. For this reason would you recommend upping the CPU Core from stock anyway (am I right in thinking I have some headroom with those core temps)?
If so then to what voltage?
Is there any advantage to running the CPU on the edge in my situation (i.e. JUST giving it enough Volts) or would I be better off giving it some headroom?

2) Is it imperative that C1E and EIST are disabled?
What will happen if I enable them?

3) There is a setting in the BIOS to enable the CPU fan speed to be controlled by (it's temp?). Am I OK to leave this enabled or should I disable this?

4) Should I run all load tests on the CPU before worrying about RAM?

5) Once I am happy with the CPU and want to attack the RAM can I use it "by SPD" or should I set the timings manually?
If manually then should I set them as per the .pdf (5-5-5-15 and 2.1V)?

or...should I increase RAM speed and voltage slowly and check results as I go with Prime95's "Blend"?
Will it be necessary to use Memtest86?

I think that's all of my questions for now. Thank you flibby.
 
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Thanks again.

I shall be running my long Prime95 test overnight and through tomorrow.

I have just attempted to up my RAM but it doesn't like it.

By default the divider is 1:1.5 and with a default clock of 272MHz this gives a RAM speed of 816MHz.

Now with my clocked machine I set the timings to 5-5-5-12 and upped the Voltage to 2.1V
The RAM won't even run at 833MHz (1:1.25) but it will at 799MHz (1:1.2).

Any ideas?
 
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