Hey everyone. I hope to find an answer to my problem here on Toms hardware. I am Swedish and couldn't find my answer on any forum swedish forum.

I am having this very very strange problem. I cannot overclock my E6600 over 300FSB. I bought a new 2gig memory stick kit from Corsair, The "XMS2 2048 gig PC6400 800 MHz" I have tried everything, Mixed with the NB,SB Vcore,Vdimm but nothing has worked.

The problem is that my screen goes comply black if i override 300FSB. First, i couldn't even use them and i had to boost the Vdimm to 2,1 for them to even work. So the screen was black as soon as i tried them but i fixed that and can overclock ONLY to 300FSB but that's where it stops.

I am not a very experienced overclocker but how come my XMS 667 mhz could make the trick and not my new 800 MHz memory ? I am not very familiar with timeings and such things. But everest is telling me they are running at :

@400 MHz 5-5-5-18
@200 MHz 4-4-4-13

Maybe it is the timing that is making this problem?

Please excuse me for my bad English, I am only 16 years old but i hope you have understood the problem anyways.

Did you set the memory Divider to 1:1 or sync mode? If not, then the divider may have taken your Memory to 900 Mhz, for the standard 2:3 configuration that gives near 800Mhz at 266 FSB.

1:1 ratio will make it run with the FSB, so 300 FSB will be 600 Mhz because of your double data rate RAM.

But the standard divider would make it 3 x FSB 300 for 900 Mhz.

Just set the Voltage to the factory required amount for the rated timings. Looks like 5-5-5-18 @ x.xxx volts.

That way you're good till like 420 FSB.

--Lupi

Well, i think i have tried that allready.

In my Bios there is a function called DRAM frequency that i think is the RAM ratio

There are originally 5 options :

DDR2-533 Mhz
DDR2-667 Mhz
DDR2-800 Mhz
DDR2-889 Mhz
DDR2-1067 Mhz

I have already tried the 533 and the auto option and none of them are working. What am i suppose to choose in the DRAM freq?

They say that my sticks need 2,1 but i am already running them in 2,1 but can only clock to 300 FSB until my screen goes black? =S

Am i not suppose to make the timeings 4-4-4-12 like my old 667 sticks that worked to 334 FSB ? =S

It is totally possible that even at the slower speed, it cant do 4-4-4-12, if its rated for 5-5-5-18.

New breeds of ram take lots of underclocking to get from 5-5-5 to 4-4-4.

Try the 5-5-5-18 and see if it works!

--Lupi

So i shall try to set my DRAM freq to 533 mhz and to 2,2 in Vdimm with 5-5-5-18 ? and then clock my FSB over 300?

If it dont work what am i suppose to do then?

Disable all CPU options, C1e, Vanderpool, etc. Disable all spread spectrum junk. North bridge voltage to 1.45ish, FSB to 400, Memory to manual linked mode, then select the divider 1:1, or Sync mode if it lists it by name.

Manually enter in 5-5-5-18 for the RAM timings and set the Voltage to 2.0.. what version do you have, the 5-5-5-18 or the 3-4-3-9 stuff? You never specify its exact speed.

Set the VCore to 1.4500 for now in the Bios, and use a x 8 CPU multiplier.

Run Core Temp and list the VID of your processor here, as well as the make and model of your Mobo, and other gear.

It's only the RAM if you have it set up wrong!

--Lupi

I dont know if it is the 3-4-3-9, this is the text from where i bought it :

The TWIN2X2048-6400 is a 2 GByte matched pair of DDR2 SDRAM DIMMs.

This part delivers outstanding performance in the latest generation of DDR2-based motherboards. It has been tested extensively in multiple DDR2 motherboards to ensure compatibility and performance at its rated speed. This memory has been verified to operate at 800MHz at the low latencies of 5-5-5-18-T1. This module is also available in a single module part.

Features:
%u2022 2048 Megabytes of memory in a pair of 240-pin DDR2 DIMMs
%u2022 Two matched CM2X1024-6400 modules
%u2022 Implemented using 64M x 8 DDR2 SDRAMs
%u2022 100% tested at 800MHz in high performance DDR2 motherboards
%u2022 Legendary Corsair reliability and service

Alright, you think it will work with your setup ?

Maybe your motherboard just can't handle the extra FSB? What motherboard are you running?

Asus P5B, it can handle it. With my 667 mhz sticks it works just fine =S

HAHA i can't believe it. It actually work. both core temperatures is on idle 30-40 degrees Celsius.

On core temp it is 36-37 and on everest it is 37-40

How the hell did this thing started to work from nowhere. What could have been the reason for all the problems? My memory timeing looked a little bit strange. it was 5-6-5 or something i don't know. I'l let it over the night with orthos and tomorrow I'll test it with 3Dmark. Thank you so very much. I couldn't have got this to work without you.

What helped??

--Lupi

hehehe, and if you did the 1.45000 VCore, you can lower it if you wanna keep that 3.2 until you find where it fails, than raise it 1 notch, and yer good to go. Prolly getting a bit more VCore than it needs right now.

If you run the program Core Temp, it will list your VID.

Please list that here when you see it?

--Lupi

Core temp sais my VID is 1.3500 i don't really know that that means but yeah.

2.1v is the voltage they are suppose to run at, its how all Corsair 6400 chips are.

VID is your starting voltage for stock speed.

It basically shows what voltages you'll need when over clocking. If it's stock at 1.3500 @ 2.4 Ghz, it will obviously need more than that for higher speeds.

Although people are constantly amazed to discover that they have about 3-400 Mhz worth of head room before you need to add VCore. That's simply due to intel leaving alot of room to err.

They want it to give you ZERO problems for at least 3 years. Their warranty period, of course!!

--lupi

So I suppose i'l try to lower my Vcore to maybe 1,4 or something ? is that a good vcore for 3,2 ghz ?

And also, Do i dare to make the dividers 1 notch faster ?

Well, you test with Prime small ffts over night at the first testing for a new setting. If thats stable the next morning, like 8 hours, you reduce the VCore by 2 notches, and then prime small fft test on all the cores for 2 hours or so, and if it has no errors, lower it by another notch, go for an hour, then another, for an hour until it fails, then add a notch, and re test over night.

You want the lowest VCore that gets you anything over 8 hours of prime small ffts on all the cores!!

keep an eye on yer temps and watch them go down!

--Lupi

Well, i actiuly tried orthos for 10 minutes and both my cores were on load like 70C, do i dare to test them over the night? will my computer shut down automaticly if they get overheated ? I only got stockcooling as you know.

I also tried to raise the dividers to 1000 mhz but they failed and I got the black screen again. Does that mean i cant overclock my memory over 800 mhz ? haha because thats kind of an evil nummber for a PC6400 sticks ?

You sure cant make it 1000 Mhz. Not many over clock that high at all. And only with lax timings. Stick with what you have, and try to remember, Memory speed is a joke. FSB to memory speed isn't.

Remember, if your FSB is the pathways that your RAM's data must take to and from everything else, how would you be able to fit 1000 Mhz in a bus that equals 800 Mhz? (FSB x double data rate = 800. So its really a single stick opporating at 400 Mhz... but two of them!)

Its okay to test, just watch them, and after 30 mins they should settle lower. Once they settle down, hit the sack! If 15 mins = 70c, then you'll prolly get to 72-73c before it goes back down.

No big deal, just watch it, as long as it levels off and stops rising, all is well. It will find a point that it settles in to for the long haul!

--Lupi

Oh I see, then i should not complain about them running in 1:1

I thank you again for your help and for your patiens with me. When I look through the thread I have asked maybe 10-15 questions haha. I'l test my system with orthos over the night, then SuperPI in 1,8,32 mb mode. An finaly test if i get any bluscreen or anything in 3Dmark 06. Does that sound good ?