E8400 Voltage Drop


May 6, 2008
I am attempting to tweak my overclock.


E8400 C0 Stepping VID 1.225
Gigabyte GA-EP35-DS3L
4 GB G. Skill DDR2 800 5-5-5-15 1.8-1.9V
Aftermarket cooler

I had the following overclock stable and running for months:

E8400 3.30GHz(367x9)
Motherboard Voltage @ 1.1875
Ram underclocked to 734MHz 5-5-5-15 @1.9V

This configuration passsed Prime 95 and memtest86+

I started to try to get more out of it yesterday, and started to get errors.

My questions are mainly about voltage drops now. I noticed them yesterday, and became concerned. Motherboard Voltage set to 1.1875 in Bios and according to CPU-Z, voltage is dropping to 1.136-1.152 Volts. This is a voltage drop of 0.0355-0.0515 Volts. This is while running Prime95. Is this a normal voltage drop, and/or is it acceptable? Just making sure I did not stress my motherboard or hurt anything yesterday trying to get "more" out of it. Never noticed Voltage Drop before or paid much attention to it.

Another question. What is a "safe" voltage to run my E8400 at max? If I try to overclock anymore, I get "hardware failure" in Prime95, which I assume is too low a voltage. If I get rounding error, that is the memory being unstable. Correct me if I am wrong. Just wondering what the "MAX" voltage I should try to set Bios at to attempt higher overclocks. Thanks for any info.


Apr 16, 2008
The VID ranges for E8x00 series is up 1.365v, this is the safe limit. The max voltage before failure or damage for 45nm wolfdales is 1.45v.

There is nothing wrong with increasing your voltage a bit more to 1.2v. It's safe and will most likely stablize your overclock.


On my P5Q SE PLUS I run my e8400 up to 4 Ghz (8 X 500 fsb) with BIOS setting the vcore to 1.36. I keep it there just long enough to run benchmarks or about 15 minutes. It's completely stable, cool too, below 60 under full load with the Artic Cooling Freezer Pro 7 fan at 2500 rpm.

Anyways, 1.36 v won't kill the chip or at least mine is still alive.


Nov 29, 2007
Each chip/board will handle things differently so please take that into consideration when we post our results.

I have had my chip up to 4.5 with bios @1.39xx (didn’t pass prime but was still cool) 1.3825 (before vdroop) it will run stable at 4.2 with idle at 38C / 58C load.
Your voltages are really low. You have plenty of headroom. The E8400 will run at 3.6 with just a slight bump in vcore. Try raising FSB to desired frequency, adjust vcore accordingly (baby steps) boot and run 3dmark 06. If it runs successfully go ahead and run prime. I use 3dmark on all the systems I build as a preliminary tool for testing stability. Based on my personal results if it makes it through the CPU test more than likely you are stable. You are fine with the voltages you are talking about so go for it. Start worrying about frying your investment when you get up to 1.36+. Just make sure when running 3dmark you keep real temp open to record temps.