Question about Wolfdale E8400 overclocking options availability

[nukesgoboom]

Greetings. i had a question about the Intel Core 2 Duo E8400 Wolfdale 3.0GHz 6MB L2 Cache LGA 775 65W Dual-Core Processor and its overclocking capabilities.

I know that in order to overclock an intel cpu, you have to increase the Bus Speed and choose your Clock Ratio and also finally choose your System Memory Multiplier which determines how fast the memory runs.

for example, right now i have a Pentium 4 cedar mill overclocked to 4.5 ghz, and my corsair xms2 series ram running at thier maximum of 800 mhz. My motherboard, a GIGABYTE ga-g31m-s2l supports to the maximum an 800 mhz RAM situation, although it also claims to support a 1333 mhz FSB? i thought that was the speed at which the processor communicates with the RAM, why would a motherboard support a faster FSB frequency than the RAM frequency?

here is what i am using in the BIOS:

Clock Ratio: 15x
Bus Speed: 300 Mhz
System Memory Multiplier: 2.66 (availabe options are 2.66, 3.33, or 4)


now, i would love to push the E8400 over 4.0 ghz like so many others have done but i need to know the Clock Ratio, Bus Speed and System Memory Multiplier options that are available with the E8400. My motherboard says in its manual that the System Memory Multiplier options available are dependent on the CPU FSB settings, so if i put another CPU in the socket will the available options change? or is that not true and the 2.66,3.33,4 options only what im going to get?

would the following situation be possible with the Wolfdale and my GIGABYTE ga-g31m-s2l motherboard:

Clock Ratio: 8
bus speed: 500
System Memory Multiplier: 1.6

thus giving both cores a frequency of 4 ghz? what are the available options that are shipped with the E8400? i should note, if i ever try to push the ram over 800 mhz then i get almost an instant crash at the windows xp desktop. also, what would happen if my Rated FSB were to go over 1333? would my computer also crash because my motherboard can only go as high as a 1333 FSB? i have seen alot of success stories of people overclocking with the bus of the E8400 into the 450 MHZ range, so surely if it is quad pumped that would be a FSB of 1800 MHZ... i have not seen motherboard go that high, or maybe it doesnt matter as much?

i guess my biggest problem is the System Memory Multiplier because i cant go over 800 mhz for the RAM, although i think its my motherboard that is picky about that, not the RAM itself.

 

[Shadow703793]

Clock Ratio: 8
bus speed: 500
System Memory Multiplier: 1.6

That should work, but not sure if the SPD can go at 1.6 on the board. I believe all gigabyte boards have the lowest SPD of 2. You can go to 9x multiplier on the E8400.

9*500=4500.

 

[Lupiron]

Technically, the FSB is the Memories pathway to everywhere! So thats FSB 333 is all. FSB (Not QDR) FSB 333 = 667 DDR2.

So you'd need a 400 FSB to truly run your RAM at 800 Mhz. Dont fall for the Mem divider hype.

And then it would be CPU multiplier x FSB = CPU speed.

So a FSB 400 vs a 333 FSB with a higher divider would easily come out in the 400 FSB favor. How can you pack 800 Mhz worth of data through a 300 Mhz bus? Just cant be done. It does manage to look like it does a TINY bit more in Synth benchies.

Already done the testing!

e8400 = 333 FSB x9 Multi for 3997.

From all I have seen, its an excellent over clocker!

Wow, nice demo! And yeah, that would work provided you can attain a 500 Mhz FSB!! And then your ram would HAVE to function at 1000 Mhz. ( 500 FSB X Double data Rate.)

I am not sure if one of the newer 300 $ board will run at 500 all day long. A p5k-e wifi hits 500 and boots for sure! I'll tell you what! That machine would be one smokin' byotch with a 500 Mhz FSB and some good RAM! PC 1000 @ 4-4-4-12 and tighten them!

Your Mobos Rated FSB is just its rating, depending on quality, it may only get a bit over that, or alot. Lots of good MoBos reach 450 FSB. Now 500 is a different story!

Technically, its your Multiplier thats holding your RAM back now. Get the FSB in sync with it, and modify the multi of your processor to get near the speed its already at!

I like to ramble!

--Lupi

 

[Lupiron]

Shadow, looks like 3.8 Prime stable is a little harder than I thought! And it gets hot, no matter the cooler, lol! Maybe its because it takes a VCore gain of .1 total to go from 2.4 to 3.6 Prime stable. So from 1.2000 to 1.3000

And so far its not prime stable at 3798.7 @ 1.4700, Well over what it took to reach 3.6, lol! That last 200 Mhz sure costs!

--Lupi!

 

[ctbaars]

GIGABYTE ga-g31m-s2l.

I have a ga-g33m and I can't go over 3.8GHz without personal discomfort with the voltage. (The G33M has a x1.6 too). So I stuck with 3.6GHz. (See my config). But I must admit, I have a very low pain threshold. Your 8x500 w/1.6mult. should work. Also I find that my NB heatsink gets too hot to touch at +0.2v. Before I push again, I plan on getting a third party HS for the NB.
Actually, I'm skeptical that you will get 500 in the 8x500. I think 9x450 is more realistic. (Because of the intergrated graphics I'm told on other threads.)
But hey. I'm just a scardy-kat novice
Tell us how you do!

 

[ocguy31]

1.47 for 3.8? YIKES. The worst ive heard is 1.42V for 4ghz. Something is going on...

 

[Lupiron]

Where'd he go? Boom?

Hehe

--Lupi

 

[nukesgoboom]

hey guys! wow thanks for all of the replies so far. so it looks like that the System Memory Multiplier is dependant on the motherboard and not the cpu? is that true? is there a place where i could find a list of system memory multiplier options for the E8400 or is it dependant on my motherboard?

i know that the highest clock ratio option for the E8400 is 9. therefore, ill have to pump up the bus speed to get my overclock really high just like everyone else with the E8400, but then again, since my RAM only goes to 800 mhz, ill have to hope for a low System Memory Multiplier.

thats what is going to kill me. Shadow7037 93, you said that the lowest system memory multiplier that gigabyte motherboards have is 2.0? so the fastest i could get the E8400 on this board is 9x400=3600 mhz? is there a place where i can make sure that the lowest SPD really is 2.0?



Lupiron, thank you for explaining to me the difference between the bus speed and the Quad Pumping effect that intel uses, i was definitly fooled by that and as such now i only have a 300 mhz FSB in reality. i fell for the 800 FSB that was listed on new eggs page and figured i would be ok with my last processor. i dont feel too stupid though, im told this is a common mistake and its quite confusing to new people like me.


ctbaars - i have not actually seen the 1.6 SPD, i was just asking if it was possible to use the 1.6 SPD with the E8400

 

[Lupiron]

Uhh, the lowest system multiplier is double the FSB. So 333 x 9 = 3.0ish, minimum memory would have to be 667 Mhz.

400 x 9 = 3.6 with yer mem lowest at 800 Mhz. (Double data rate has to be at least double the FSBs rate.)

So looks like you'll be stuck at 3.7ish unless you loosen the ram timings or get faster ram. Most name brands will get at least 425 x 2 for 850 + if you have good stuff, you'll get more.


I think that 2.0 for gig boards is the sync mode. 2 x fsb = sync.

--Lupi