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Help with xeon e5450 oc

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New Member
May 4, 2017
I want to oc my xeon e5450, but when i set 3.6 GHz with auto vcore i have "fatal error roundig was 0.5, expected less than 0.4"
I tried to set 1.25V but Windows didnt run. With auto vcore on 3.6 GHz i had 1.123-1.246 V i cpu-z. How can i fix this?
Last edited:


Jul 23, 2016
What's up Sebido, I am not familiar with your specific processor but I'll see if I can help. I also didnt check the platform. But Intel ark says it's 3.0Mhz base and from 2007. So I'll assume it's 775socket.

For one, not sure how you are trying to overclock, but 600 mhz is a large amount for the start. 1333 may be the maximum rated fsb of that socket.

To start, set everything back to stock. Stock clock, stock volts. Get a baseline run to check temps and loads. Also check fan speeds and make sure everything is in good working order. Record all baseline numbers or get screenshots for your records.

Here is an extra step, but well worth it. Go through your bios before you play with anything, especially voltages and make sure you understand what each feature is and what it does. Then enable or disable things you do or don't want.

Then go into device manager and make sure your storage communication speeds are set correctly.
See under IDE for Ultra DMA version and ensure they are set correctly. They must be first set correctly in bios. The bios will read what your hard drives are capable of but may not be properly set. Make sure that's correct before making changes to device management.

The go into your windows power plan and make you have it set the way it should be for what is important for what you want. Many choose to set windows to performance to ensure the power plan isn't hindering finding a ceiling.

Something important within power plan if you don't set to performance. As I prefer balanced, is the PCIe settings. Ensure it is set correctly.

Now we are starting with a base bios if you have also gone through everything else and set it they way you want. Good idea to get another baseline before you start making larger bios changes.

From here make sure you change one thing at a time and get a run watching stats and recording min/max numbers.
Some of the 775 boards only give you the option for an fsb overclock. Don't go over 1333 on the fsb, even then it's on the high side.

Best to overclock with the base clk if possible. If fsb is all you have then leave it and get more performamce elsewhere.
For instance, what is the reason for the overclock? Does a cpu overclock move towards the objective? Has the cpu become a bottleneck?

That's alot to start...If there is no overclock to be had, you can still increase performance of the cpu by
adjusting the cpu fan. Use a loading program to see if its throttling, use another program to find out the specific temp it throttles at. With stock settings for the smart fan, it's gonna throttle.

Do these things before deciding to start playing with the bclk. Let us know how it goes.
Last edited:


Jul 23, 2016
I thought about it, sounds like your doing an fsb overclock to 1666. So the other things first. For that kind of fsb overclock your gonna need to slow that memory down most likely. But as I mentioned, do everything else first, including deciding if it's even necessary for your purpose.


Jul 23, 2016
Its sounds like you found a stable overclock so that's good.

If you want better performance in games you'll get alot more from overclocking the gpu, rather than the cpu. That is if it's needed.

It's common to overclock the cpu for games if the cpu is holding back the gpu. (bottleneck) or if the game is cpu intensive. But that depends on the game.

If the cpu is not holding back the gpu, your performance increase will be much smaller. Again that depends on the game.

If the goal is just to get every bit you can then that's just what some people want.
Something to keep in mind though is that if you overclock the cpu too far, you can lose cpu physics. That will hurt performance of certain games.

Lastly, you may have hit a thermal limit.
Your cpu is a Xeon, the Q6600 was known to hit 3.4Mhz but was a max overclock. Your at 3.5, so it sounds good.

Lastly, the mismatched sticks can hurt it's maximums when overclocking.