PC switches off then on when powering up

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Hi All,

Can anyone explain this to me.

I've just upgraded to dual core with the following components:

Conroe 2.13GHz
ASUS P5B-VM Micro-ATX
GeIL 2GB PC6400C4 800MHz Dual Channel
PowerColor X1950XT Pro 256MB
Enermax 500W PSU

Now whenever I power up my machine it starts to power up, the power light then flashes, it powers down, then a few seconds later it powers up properly and runs perfectly fine for hours.

Why would it do this whenever I power up? :confused:

The weird thing is, it also did it using my previous socket 478 setup on a 460W PSU. Although I've just used these components in a HTPC system, which doesn't have this issue.
 
i also have the same problem......

but i only get it when i turn the power supply off from the switch on the back or unplug from the wall. just turning off and on from the case and its fine.

so obviously this isnt a problem but im curious what is causing it !?

Anyone ??
 
Just helped a mate put together some new parts and his pc now does the same thing I thought i was down to him having a poor power supply as it was only a 350watt that came with the case

Specs are
E4300 @ 3.2ghz
Abit ab9 pro
2 gig OCZ ram
x850pro

You guys got decent psu's to rule this theory out? So I can tell him he needs a better one
 
I get this on my DS3 after some failed overclocking attempts. Shorting the BIOS reset switch on the motherboard for few seconds sorts it out. It is the system trying to fix itself after a failed POST.
 
i have the asus pb5 deluxe which does the same thing, apparently its to do wi the changing of straps going from 1066/1333 to 1600 or whatever. it only happens why my 6300 is overclocked.

something to do with the 965 chipsets iirc
 
I have the Asus P5WDG2 WS Pro mobo with the E6600 processor, when running it at stock and speeds up to 2.88GHz, when I would reboot, it would do so as normal, but once I overclocked above that, when I would reboot the machine, it would cut out for a period of 1-2 seconds, then start up again and continue working properly, I emailed Asus Support the following:

I wrote:

When I reboot, the computer switches itself off (ie. powers off) by itself, then after 1-2 seconds, it
switches itself back on (ie. powers on) again, and continues to boot into Windows.

This issue has been well documented on different Forums on the internet, even in Asus's own Forum.

When will Asus release a BIOS update to fix this annoying problem.

Reply from Asus:

Sir, this problem only appears when you overclock your CPU, right?

You know Intel has overclock limit on their chipsets,

to overcome this limit, on a warm boot, system will shutdown power for few seconds, then re-power
the chipset to make your overclocking setting work! s,

it is not a bug or hardware failure, don't worry about it.


Thank you for using ASUS products and services!

I wrote:

As you stated, this issue only appears when overclocking, it is good to know it is not a not a bug or
hardware failure.

Nevertheless, it is still a most annoying issue, is there any way to remedy it (apart from not
overclocking), so that it does not occur?

Many thanks for your help.

Asus wrote:

Sorry sir, nothing can get rid of this,

The board chipset need re-powered to overcome the overclocking limit,

that is the reason.....


Thank you for using ASUS products and services!

Hope this info may be off help. :)
 
Not running Core2 here, but my board does that by itself when i have a failed OC, not enough voltage, too much clock etc...... Its like an autorecovery feature, saves having to clear CMOS.....

Or at least how it is with my board (939 Epox 9NPA+ Ultra). Its definately a feature, this is my 2nd one of these boards, they both do it, and it makes OC'ing so much easier not having to touch the CMOS jumper. Second out of choice, not destroying the other one (in case anyone wondered).
 
harris1986 said:
i stand corrected but i was referring to the op's board which is a p5b, which i'm aware have been resolved in later bios revisions!

No problem, I was just relating the issue I was experiencing with my mobo, incase the same thing was happening with KevinCB'S. :)
 
the bios updates cured this problem a long time ago! i too had it with my p5b deluxe on the stock bios, after i upgraded to the latest problem solved!

No it didn't, I am running a P5B deluxe wifi edition with the latest BIOS and my board does exactly the same thing. Also Asus response is rubbish is as well.

I've done some testing with this board to find out what's happening. The upshot is that as things stand just now I have my E6600 OC'd at 3 and a bit GHz. When I power off and leave power running the system boots without issue to the full 3Ghz. If I shut down and power of at the wall and then reboot it used to resest the system too stock values on the CPU / FSB but maintain any Voltage adjustsment made to the Vcore. (that's quite worrying for a start.) I have of late just found that fully powering off and then powering up resets the system to 2.9Ghz. A somewhat funny value to say the least. Further investigation found that this 2.9Ghz was a setup I had stored earlier in the Asus OC profiles (number 1 slot) within the BIOS.

The system is stable at 3.0Ghz, and doesn't shut down to power up for overclock as Asus stated otherwise it would come back up with 3.0Ghz instead of 2.9Ghz. It sounds like an attempt to recover from a failed OC that just hasn't been implemented very well.
 
This happens randomly with my p5b deluxe too. Most of the time it reboots, and powers up from a cold state fine. But every so often, when power is applied from a cold boot, it'll power on for a couple of seconds, power off, and then power back on again.

It never loses my OC settings though.
 
well iirc asus did fix the problem a lot of people with the p5b's had the same problem (myself included) and a bios update fixed it! i'm running the 0804 version so try updating to this version and seeing if you still get the reboots?

*also on a side note what method are you updating the bios?
 
OK, I have updated the bios to 0405, but it still hasn't made any difference.

I updated it using the built in bios flash utility by pressing Alt + F2 on startup.

Oh, and I also haven't OCk'd anything.
 
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my mistake didn't see the micro board, well maybe the update only applied to p5b deluxe's :confused: , as mine and a lot of others was fixed after a update! bit strange asus not fixing the problem across all boards!

just as a trial try giving your board and cpu a slight overclock and see if it double restarts still? i occasionaly get a double reboot on mine only when the cpu is at stock tho!
 
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