i keep receiving this error
Rounding was 0.5, expected less than 0.4
Is that due to low ram voltage?I have 2GB (KIT 2x1GB) DDR2 800MHz PC6400 CL5-5-5-12 CORSAIR TWINX XMS2 and i will change it tomorrow for 4GB (KIT 2x2GB) DDR2 1066MHz PC8500 CL5-5-5-15 CORSAIR XMS2 DOMINATOR.Will this solve my problem?
PS.i move the ram voltage over 2.2V now current FSB is 468(4.21Ghz) and after 21 minutes on small FFT on prime95 i got this error
FATAL ERROR: Resulting sum was 1475852091920711, expected: 1475852024811846
Hardware failure detected, consult stress.txt file.
Does that mean i ve reached my CPU limit?My configuration is
GIGABYTE EP45-DQ6
2GB (KIT 2x1GB) DDR2 800MHz PC6400 CL5-5-5-12
Intel E8400
EVGA 9800gx2
2 SATA II 500 + 750GB
Thanks for your time
temperature s out of the question cause i have a large heatsink and when prime is working RealTemp reports just 62C

I Forgot to mention those were while using Prime95

FSB 648
It means your FSB is running at speed 4X648=2592
I do not think there a motherboard that can run at this speed
You can hardly acheive 2000
Can you list your OC settings
lower FSB to 500 and install 1066 RAM and see
I beleive your North Bridge is failing

damn sorry!i ment to type 468 -.- its 9x468 ive corrected the 1st post

OC settings please
And by the way at 468 you ram is running at 936MHz
I don't know what is your ratio and whether you mobo can run at such combination
but definitely will not run at ratio 1:1

i ve posted images from my bios its my 1st overclock so dont be harsh on me until FSB 463 pc on 8 hours with Prime Blend was completely stable
MCH fq cant change to 200/266/333/400MHz

anyoneeeeeeeee?

I'm no professional overclocker by any means but I really think you do not have enough voltage going to your cpu. I was unable to reach 4000mhz without surpassing intels rated max voltage of 1.3625V. On the box my cpu came in it says the max voltage is even lower @ 1.25v.

Take a look at this link and you will see that the guys that hit 4200mhz had a vcore of 1.45v. It's your choice if risking your cpu's useful life is worth that little extra performance. I have mine at 3800mhz @ 1.275v with no worries. Ran for 24hours Prime95; while prime95 was running I played Bioshock for an hour and did a 3dmark06 test, 0 errors. The only other voltage I increased was my ram, +1, which brought it to 1.9v and it's rated at 1.8.

http://www.legionhardware.com/docu [...] id=717&p=0

Edit: After posting I decided to give 4000mhz another shot. Currently running @ 1.3625v, Orthos has been going for 5.5 hours . But yea, 4200mhz will require a bit more juice.

rolf i was running orthos for 9 hours and then i received an error at 4.16GHz pretty weird huh

That voltage is very low for 4.0+

a vcore of less than 1.5 is considered safe.
The VID (which is what the box would be labeled) does not indicate the maximum voltage the CPU can be run at but rather the max voltage required/needed for your chip to run at its stock freq.