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E8400 OC

Last response: in Overclocking
December 26, 2008 6:40:54 AM

Hello all! Hope you had a jolly Christmas ;)  . Ive been trying to OC my e8400 CPU this holiday and havn't gotten far. I have the stock cooler, and basically no OC experience. Check my setup for everything, but I have the Asus P5Q-Pro. Now I right now have the rated FSb at 2000 MGHZ by making the FSB 500 and CPU multiplier at 6. This OC has been in Prime95 for 10 hours, at 1.128 volts (see screenshot). Now temps are very low, and Im very happy about that! How could I get this to 3.6 stable? Because... I have tried on my own with no luck, maybe 30 minutes MAX of Prime95.

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a b à CPUs
a b K Overclocking
December 26, 2008 7:23:34 AM

awesome .

You are revving the engine of your car in first gear to make it run at the same speed it always used to in 4th gear
December 26, 2008 7:58:56 AM

^another phailed car-computer analogy. :lol: 

are you blend testing that prime95? i understand you're trying to find the max stable FSB before you push up the multiplier... make sure the RAM is at its rated timings and voltages.

are you sure you don't want to try for at least 533fsb? may as well keep pushing it, just make the RAM timings obscenely high until you have found the fsb limit, then lower them gently.

once you have hit the fsb you desire/are limited to, increase the multi until its around the stock speed, then up it .5x multi at a time until it fails SMALL FFT's. blend testing for FSB, small fft's for multi k?

whats with the 3450 as a side interest? i take it no gaming?
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a c 172 à CPUs
a c 197 K Overclocking
December 26, 2008 9:55:09 AM

Stock cooler?
a b K Overclocking
December 26, 2008 10:17:19 AM

if u want 3.6 its easy just change multi back to 9 and have fsb set to 1600 and voila. 500fsb is quite fast but your multi is crap you will gain more speed bu useing a higher multi and lower fsb. im running my e8400 at 510fsb but on a 9 multi.
December 26, 2008 7:42:57 PM

Yes I am using the stock cooler. So it sounds like you think I know how to OC.. well I dont. Also is it better to have 500*6 or 333*9? So yeah my Mushkin REDLINE is at 5-5-5-12 and 2.0V, or in other words stock speed. And yes that was a Prime95 blend test. So now I am satisfied with the 500, I guess, though 533 would be nice. So push the FSB to 533 and raise RAM timings to say 6-5-5-18? Then do what type of Prime test. Oh and after it is stable at 533 I just raise multiplier right? So 533 at 5.5 becomes 6, then 6.5?
December 26, 2008 8:30:03 PM

Oh and my 3450.. well I just bought that because needed a grpahics card, and didn't have enough cash to buy a 9800gt. In a month Im purchasing a Zotac 9800gt
December 26, 2008 9:09:04 PM

As the proud owner of an E8400 since march, all I have to say is, YOURE DOING IT ALL WRONG!

Please take that lightly though, because I'm going to show you what to do.

First off, read this online article about overclocking Core 2 Duos: it's the best guide online.

That will give you a good overview as to what you should be doing.

Now, for making your E8400 run at 3.6GHz - its really easy, I nailed 3.6 on the first try. Now, im at 4.0.

Multiplier:9 - I've seen people get fast numbers by running a low multiplier, but frankly, just don't do it.

Ram speed:400Mhz

FSB: 400MHz - it's important that the ram speed and the fsb are matched. Assuming you bought DDR2-800 ram, this should be a snap.

Vcore: 1.25 - this is the stock (as in, out of the box) voltage for the E8400. 1.128 volts? You're under powering it significantly, making it a huge risk for being unstable.

PCI frequency - 100MHz. The stock frequency. But worthwhile setting.

Your ram: go to the website of the manufacturer (give me the model, and Ill even look it up for you :)  and find the stock voltage ( example: 1.8V) and the timings (ex: 5-5-5-15). Oftentimes, the ASUS bios will automatically set the RAM to a voltage that is too low to be stable, and then sets the timings slower than they need to be (lower, the better)!

set these basic settings, and it should work perfectly, with no problems.

Overclocking, once you get the general idea down, is a LOT of fun. Heres some things I might suggest you invest in:

A larger cooling fan. If you ever take it past 3.6GHz (which your E8400 will run forever, BTW), I suggest getting something other than the tiny aluminum fan Intel ships with these. I bought a Zalman 9700NT, but since then there are more smaller and more efficient coolers now. Read some more, look around.

I don't know what Ram you bought, but its the other bottleneck on the E8400. Instead of DDR2-800, I suggest DDR2-1066 if you want to crack 4GHz. G-skill is cheap and good (with no silly mail-in rebates, if you hate those), but the best ram going right now for you IMO is Corsair Dominator and Crucial Ballistix.

Hope all this info helps. I learned it the hard
December 26, 2008 9:42:08 PM

+1 to xstang.

Here's the best heatsink for you right now: Xigmatek HDT-S1283 with Thermalright LGA 775 Bolt-Thru kit. You could also go with the Sunbeam Core Contact Freezer if you'd like.

To xstang's list of preferred memory for overclocking, I'd also add Mushkin Redline DDR2-1000, which 5Toes apparently already has, by his signature.
December 26, 2008 10:12:17 PM

Mushkin redline is good - it seems to overclock fairly well, but the fact that the heatspreaders dont perfectly cover the chips half the time is a lil disturbing.

Personally, I've got OCZ reaper, which honestly is overkill, but anything with a decent mail-in (again, look around) should work fine.
December 26, 2008 10:34:59 PM

@xstang he's already running at 500fsb... imo put the timings at 6-6-6-18, try for 533 then drop the timings one at a time until its unstable. then up it one until it IS stable! =]

then once you have eliminated the motherboard/ram as the overclocking issue, start on the cpu. this leaves no doubt that the cpu is the limiting factor. the idea is to reduce the variables... if you're only changing one thing at a time, you know one thing is the problem!
December 26, 2008 11:15:48 PM


@xstang he's already running at 500fsb... imo put the timings at 6-6-6-18, try for 533 then drop the timings one at a time until its unstable. then up it one until it IS stable! =]

Yeah, but with a multiplier of 6...lets bust out the TI-89 and do some simple math....

6*500= 3ghz....the factory clock !

Mind you, I've seen people OC their computers by dropping the multiplier and running a higher FSB - however, everytime I've seen a benchmark of an OC done that way, it's slower!!!
a b K Overclocking
December 26, 2008 11:55:03 PM

he has shown he can get to 500fsb stable now he has to raise multi to see how fast it will go at 500fsb, you should never run a lower multi unless its a e2180 with a 12 multi i think lol.
December 27, 2008 12:11:43 AM

Wow, what an argument. Hell yeah I got Mushkin, it's the best RAM company on this Earth! So I think 500 FSB is plenty good. OK so since I have the voltage low (nice temps ehh?) at 1.12 V, I should keep it there and set my REDLINE's timings to 5-5-5-18 and RAM speed to 1066 and the FSB to 533. Is 533 the max FSB on the P5Q-Pro. Then run Prime and get it stable. Ive had this RAM at 5-5-5-18 at 1066 before no problem, but with everything else stock. Then to shoot for 3.6, that's 533*7 or 3.7. If I do this the vcore should be at like 1.25 right? Then I drop it slowly until it's unstable and raise it one notch?

But is it better to run 500*6, or 333*9, or in other words higher FSB and lower multi... or lower FSB higher multi?

And since Im only 14, I want to say thanks for helping me out so much :) 

Soon I will buy a ZALMAN 9500 and mod it with a Silverstone FM121 120MM fan (
December 27, 2008 12:50:36 AM

Quote:But is it better to run 500*6, or 333*9, or in other words higher FSB and lower multi... or lower FSB higher multi?

Hey, rearing my huge head on here again. Personally, I think running the highest possible multiplier is the best route.

That is:

9*400= 3.6

Running a lower FSB will net you another nice little bonus: since you're not running your RAM at the max speed (800), you can run it at faster timings, say, 4-4-4-12, which is blazing quick.

Quote: If I do this the vcore should be at like 1.25 right? Then I drop it slowly until it's unstable and raise it one notch?

Actually, not a bad idea... The lowest I'd really attempt togo is about 1.2Vcore, and let prime test itself for HOURS at that voltage - as long as the chip doesn't crash, using the lower voltage will extend the life of the chip (we're talking over a period of years here) and keep the temps under control.
December 27, 2008 1:04:55 AM

Yeah Im happy Im running my CPU at 1.12 right now! It's really low huh? OK nowIve heard DDR2 1000 with a CAS of 5 is the same as DDR2 800 with a CAS of 4, because a lower cas, by one, is 20% faster.. And higher FSB means faster communications with CPU. So I think over the enxt week I will raise the FSB to 533 and 1066 RAM, with timings of 5-5-5-18. Then I will set the VCORE to 1.25 and the multi to 7 instead of 6. Thats 3.7 GHZ final speed, over the 3.2 at 6 multi. Then I can try to push to 4 with a multi of 7.5. Now what do you think the VCORE would be for 4.0, considering I have running very low right now..

Oh and it is always best to have a 1:1 ratio for your FSB and RAM right? Because when I got the FSB to 500, as soon as I made the RAM 1000, it was stable :D 

Oh and would I ever need to mess around with the Northbridge voltage, since I have high FSB speeds?
December 27, 2008 2:36:35 AM

OK 5Toes, looks like you've figured out a lot more than you let on. :) 

By now I think that you can see how the posters on this thread fall into the 2 different camps of:

1. lower multiplier and higher FSB

2. higher multiplier and lower FSB

Without opining on who is right, let me add one other twist that has been absent so far, or how to max both CPU and memory. See if you can try to aim for this set of parameters:

FSB: 445 MHz
CPU: 4.005 GHz (at 9x multiplier)
RAM Divider: 1.2 (or 6/5, in fractional terms)
RAM Speed: DDR2-1068 at timings of 5-5-5-12

Look around on the Net for the subtimings and other related BIOS settings for Mushkin Redline, as that should help you get to that high overclock.

You'll need a really good heatsink to get there. Instead of your Zalman (unless you really like its looks), try the Xigmatek HDT-S1283 or Sunbeam Core Contact Freezer, with corresponding Thermalright LGA-775 Bolt-Thru Kit.

You'll have to figure out all of the voltages yourself, but I think you've got that down pat too! ;) 
December 27, 2008 4:56:36 AM

Well I REALLY dont want to go over 1.36.. because that burns the cpu up.. Oh and I only have the stock cooler, Im getting the Zalman 9500 soon. And It will have the best 120CM fan on the market, pushing 100cfm. So I think I will be fine. Well I think Ill run the 1066 and 6.5 multi to get 3.4 at say 1.2V to start. Then Ill work up to 4. That is.. if my CPU cooler can get me there... To work up what is the procedure for this? Is it:

1 - Raise Vcore about .15V or .2V and multi/FSB to desired level
2 - Try to POST, if you can't raise VCORE
3 - Raise VCORE until you can get into Windows
4 - Run PRIME95 until stable, by raising VCORE until stability

How much should I raise VCORE at a time? 1 notch in bios?

Also is best to have 1:1 ratio for most overclocks, or is there something better?

Why those Parameters?

And heres what Im thinking, for my final overclock with Zalman 9500 with Silverstone 120MM Fan pushing 110CFM

FSB - 533
Rated FSB - 2132
CPU - 4.26 GHZ (533*8)
RAM - 1066 at 5-5-5-18

And finally (sorry I write soooo much) would I ever need to F*** around with the NB voltages?