Simviation Forums

So I've finally built my new system; Asus P5B Deluxe with a Conroe Core 2 Duo 6600, and a rev 2.0 PSU, eVGA 7950GT ... but it won't boot. No video, no beeps, nothing.

I suspect the RAM...  2x1GB G.Skill F2-6400CL5D... in looking around, I saw some claims that this board will not boot at all with this RAM, or it will boot but BIOS will not work, but after reading several "OK out of the box- works great" reviews, I figured I'd save a lttle money and give it a shot.

Also heard no bad news about using the 7950GT with the P5B, and it powers up... other than the boot failure, everything seems fine. All components getting power including hard drive; all system fans working; PSU is connected properly and appears to be functioning normally. Took everything apart and double-checked the CPU placement, etc... should be fine.

Haven't contacted mfr's tech support for RAM or mobo yet, but I'm curious as to what opinions I might get from our SimV stable of builders...probably should have done that prior to buying, but I thought I'd checked everything out pretty thoroughly.

Is there any simple way to determine which item is at fault (mobo or memory... or CPU)? I don't have any other 240-pin RAM handy, so that's out. I triple-checked everything, tried power-up with no RAM (which produced the expected beep code, but of course no video). The beeps were encouraging as far as the board is concerned, but I suppose it could still be bad.
Also tried clearing the RTC just for laughs... no joy.

Looking through the Asus RAM compatibility list in the user's manual  shows no mention of any G.Skill RAM, and so far I can't find any of the PC2-800 models listed there available for sale online... not encouraging.

Is the motherboard BIOS up to date for the Conroe CPU?

If you happened to get a motherboard with an older BIOS that does not support the Conroe, it wont boot. Its a know issue allot of converts from AMD to Intel had kittens over because in order to get it to work you need a temp Intel CPU to do the flash before installing the Conroe.

That also includes BIOS support for the 7950 video card.

I may be wrong but it is a possibility.

According to this the memory should work in that board and this thread discusses issues....

http://cc.msnscache.com/cache.aspx?q=41 ... FORM=CVRE2


They also mention something about no post unles memory voltage is raised for GSKill which requires a single stick that will work so you can get into the BIOS to raise the memory voltage.

Just throwing things out there for you to look at

The P5B range are all 965 chipset based, which are specifically designed for Core 2 duo, so no compatibilty issue for the mainboard.

What is a Rev.2 PSU?

I've read about lack of BIOS support for the GF7950GT but I haven't heard about it on these newer boards, though it's possible. I don't think it would stop the boot process though would it? Again, not sure.

As Nick pointed out, the ram may need a kickstart with another module to get it configured so that it will boot, that kinda sucks and is most likely the problem IMHO.

I never did like the CAS5 offerings in PC6400 from G.skill, there were some modules designated as ZX that were cheap as well for cas4 pc6400, but they were superceded by the PK designation. The PK PC6400 are slightly lower voltage than the ZX. The ZX only worked on Intel chipsets, not sure why, but it could have been a voltage issue.

A lot of PC6400 appears to be re-worked slower ram that has it's voltage pumped up and spd chips modified to run at 800mhz.

Personally, I'd look to get a refund or a trade on the modules. Perhaps offer the supplier some more cash to get something a bit better, like the ZX, PK, or HZ (if you want to blow some cash). He'll be more likely to swap if you upgrade.

Corsair and OCZ make some modules as well, not sure what to recommend there except try to get a CAS4 module in PC6400. If cost is prohibitive, drop down to a quality set of 667mhz ram modules, At least they should boot, and if they are Cas4 you'll probably squeeze more out of them, a noob I saw today with a P5B had 667mhz modules running at 800mhz and didn't even know it. (and they were just Kingston modules)

Out of curiosity. did you try booting with a single stick or try combinations of different slots, I know you had the ram in the correct slots.......... ie. try slots 2 and 4 instead of 1 and 3 (not sure how they are numbered)

Here is another thread on this.

http://forums.whirlpool.net.au/forum-re ... m?t=579428

From that thread......

"the P5B has a lot of bios updates in August but from what i can see now it works with all sort of rams on the market in the last 2 weeks."

If you could get the thing to boot and get a bios update...... who knows, your ram may kick in...

What is a Rev.2 PSU?

Apparently, Rev 2 is more recent, and many have made the mistake of using a Rev 1.2 PSU with this board... it might be all about the EATX 12V connection that's required in addition to the main 24-pin connection.

I've read about lack of BIOS support for the GF7950GT but I haven't heard about it on these newer boards, though it's possible. I don't think it would stop the boot process though would it? Again, not sure.

I dunno either... but in my preliminary research (mostly in NewEgg reviews), there seemed to be more "OK" reviews than "NFG" reviews for this GPU/mobo combo, just as with the CPU and even these RAM modules.

As Nick pointed out, the ram may need a kickstart with another module to get it configured so that it will boot, that kinda sucks and is most likely the problem IMHO.

Yeah; too bad my other rig is PC2700, so I have to either buy more RAM at Worst Buy or someplace if I want it done this weekend, or return these and ugrade. Unfortunately, after this expenditure (over $1500 and haven't even bought the new monitor yet), I'm tapped out until Friday, so neither action is an option just yet.

I never did like the CAS5 offerings in PC6400 from G.skill, there were some modules designated as ZX that were cheap as well for cas4 pc6400, but they were superceded by the PK designation. The PK PC6400 are slightly lower voltage than the ZX. The ZX only worked on Intel chipsets, not sure why, but it could have been a voltage issue.

A lot of PC6400 appears to be re-worked slower ram that has it's voltage pumped up and spd chips modified to run at 800mhz.

Thaat's interesting... there is mention in the Asus manual about not using "128 Mb chips or double-sided X16 modules"... not sure if that applies to my sticks.
I'm beginning to think that it was foolish to not spend about $80 more for some OCZ or Crucial sticks, although reviews of those with the P5B are mixed, also.

Personally, I'd look to get a refund or a trade on the modules. Perhaps offer the supplier some more cash to get something a bit better, like the ZX, PK, or HZ (if you want to blow some cash). He'll be more likely to swap if you upgrade.

That is where I'm leaning...New Egg will take these back for a refund, although I think I have to order anew for an upgrade; I'll investigate.
 And  I just saw in the manual that there is an updated Qualified Vendors List on the Asus website; might have a look there to be sure, and also to see if they recommend something I can actually find and afford.

Out of curiosity. did you try booting with a single stick or try combinations of different slots, I know you had the ram in the correct slots.......... ie. try slots 2 and 4 instead of 1 and 3 (not sure how they are numbered)

Oh yes... tried just about every combination. The only thing that gets the thing to even act like it might start POST is no modules at all, but of course the mobo just beeps and refuses to budge when I do that.
Should it be able to crank up the GPU and show me BIOS with only its internal RAM?
Many thanks for the help, guys... I think I'll check in here again before I make my next move.

I was not aware of the inherant Core2 support...

Just to make sure the PSU is not the issue... post the 12v, 5v and 3.3v specs

It must also have BOTH a 24pin and 4-pin/8pin EATX12V power plug. If that plug is not in place it wont boot.

There have been a slew of BIOS updates for the board, including updates for the 7950 card but I see nothing that would cause a boot failure.

Still.. when you do get it lit and stable I would check the BIOS number it is running and and flash it properly with the latest release before going any further and installing Windows.

I assume you mean the PSU trip points? If so:

+3.3V@32A, +5V@35A, +12V1@17A, +12V2@19A, -12V@0.3A, +5VSB@2A

And yes, it has the additional 8-pin; it is connected properly.

I assume you mean the PSU trip points? If so:

+3.3V@32A, +5V@35A, +12V1@17A, +12V2@19A, -12V@0.3A, +5VSB@2A

And yes, it has the additional 8-pin; it is connected properly.

12v looks too low for a 7950 video card. I believe it requires a minimum of 22A on one rail.

I will check it and post back

If only you could take it to some friendly DDR2 to get it fired up, flash the bios, you might be ok.... you must be chomping at the bit!

12v looks too low for a 7950 video card. I believe it requires a minimum of 22A on one rail.

I will check it and post back

I dunno; this card has an extra power port, but the PSU provides a connector for it. No amperage rating listed in the material provided with the GPU... thought I understood that as long as I wasn't trying to run two of these cards, this particular 500W PSU would do the trick.
Thanks for the help, and I think you might be on to something, there.
I almost hope you're right: a PSU upgrade would present far fewer variables than switching RAM, I reckon.

The BFG require 22A minimum the EVGA is different:

Minimum of a 400 Watt power supply.
(Minimum recommended power supply with +12 Volt current rating of 18 Amp Amps.)
Minimum 500 Watt for SLI mode system.
(Minimum recommended power supply with +12 Volt current rating of 28 Amp Amps.)


It still looks like the 12v rails on that PSU are very weak for the hardware you are running.


I still think it is very possible you are dealing with the GSkill memory issue however 17A and 19A for 12v rail current seems very low for that hardware.

Watt rating does not mean squat.. I have seen 650watt PSU's that would not run anything decent in hardware. Watt rating is a game.. the numbers you posted tells the real story.

Lets assume the PSU is dual rail 12v and each 12v rail is limited to the numbers shown on the rating... That would mean you need a minimum of 18A AFTER everything else that is being pulled off that rail has been fed.

So if you have the 17A rail plugged into the video card, it wont run it anyway... but if it is the 19A rail, then all other devices pulling 12v must be figured into the mix before you can say the 19A is enough.


Let me put it like this... 18A is the minimum so even if you were making that spec, it would most likely run hot and doggy even if it was booting.

If only you could take it to some friendly DDR2 to get it fired up, flash the bios, you might be ok.... you must be chomping at the bit!

Yes... "chomping" is pretty accurate... I've pretty much given up flying FS9 on "Old Bessie", aka Build #1... so close to what I'm after, but very frustrating. And I really need two machines up and running so one can be doing chores like recording and rendering video while I fly the sim on the other... when I finally get all of this nonsense straightened out, I will be looking at a quantum leap in my whole computing experience.

But I'm being mellow about it. I have the simpit to work on; it's a lovely weekend and I'll be taking Peg out for a romp at the dog park shortly... kinda broke until Friday, but life is good.

Why spoil it all screaming on the phone at some poor bastard in India  trying to find out what's wrong?

The BFG require 22A minimum the EVGA is different:

Minimum of a 400 Watt power supply.
(Minimum recommended power supply with +12 Volt current rating of 18 Amp Amps.)
Minimum 500 Watt for SLI mode system.
(Minimum recommended power supply with +12 Volt current rating of 28 Amp Amps.)


It still looks like the 12v rails on that PSU are very weak for the hardware you are running.


I still think it is very possible you are dealing with the GSkill memory issue however 17A and 19A for 12v rail current seems very low for that hardware.

Watt rating does not mean squat.. I have seen 650watt PSU's that would not run anything decent in hardware. Watt rating is a game.. the numbers you posted tells the real story.

Bloody hell...I think you're right.
I knew there was more to it than total wattage; that's really more an indicator of its consumption than the rail specs... but I thought I was good to go. Should've over-spec'd, and I may just do that for the hell of it, so I don't have to worry about it, especially if I upgrade graphics later (probably going to go DX10 with FSX when things settle down in that world).

Bloody hell...I think you're right.
I knew there was more to it than total wattage; that's really more an indicator of its consumption than the rail specs... but I thought I was good to go. Should've over-spec'd, and I may just do that for the hell of it, so I don't have to worry about it, especially if I upgrade graphics later (probably going to go DX10 with FSX when things settle down in that world).

Here is what I would do for farts & giggles...


Unplug the tower and hit the power button a few times to de-energize the PSU. Pull all but 1 stick of memory. Disconnect all the drives in the system. Run only the motherboard and video card. Clear the CMOS.. check the manual on how to properly do that...

Power up and see if you get something out of it. If not, swap the 12v for one off the other rail and try again.


If still not... Some Asus motherboards allow the INSERT key be held down to load a boot BIOS when overclocking fails... this is done by hitting the power button and then hit and hold the INSERT key until you hear the beep and boot.

Bloody hell...I think you're right.
I knew there was more to it than total wattage; that's really more an indicator of its consumption than the rail specs... but I thought I was good to go. Should've over-spec'd, and I may just do that for the hell of it, so I don't have to worry about it, especially if I upgrade graphics later (probably going to go DX10 with FSX when things settle down in that world).

For DX10 you are going to need a hell of a PSU.. be ready for that expense.




As for the combined 12v A... some PSU's use a combined output, in other words if the amps drop on one rail the other will allow it the slack. Other PSU's are strict about that... if the A drops on rail 1, B wil not allow it to have anything.

It depends on the manufacture of PSU

PC POWER AND COOLING is my best friend. Although expensive... when they tell you it has the power, you can bet the bank, farm and your first born.. it does.

Seems all the rhetoric and awards about power saving features is so much more lip service, or in reality a way to keep power requirements within domestic limits!

3 phase PSU's anyone ?