December last year I did an upgrade of my system.

Q6600 – Second hand
Asus p5q pro – New
2 x 2 gig OCZ reaper 1066 – New
WD 640g – New
Antec ATX TruePower 550W ver2 – Previous system.
Asus 8800 GTS 512 – Second hand

Anyway about a week ago my computer would not boot. Previously working fine since December. It just turns on and all the fans stay on but nothing appears on the screen.

I have updated the bios to current.

Mem test and they always fail in dual mode but are fine one at a time.

Plugged an old 6600 gt card in and it boots ok and system seems to operate fine.

Plug the 8800 gts in and it now blue screens as it goes into windows.

The psu does not have an 8 pin connector for the mother board and I just plug the 4 pin into half of it. Not sure if this is a problem or not? It used to work fine.

Anyway I am a bit stumped if it is the video card seeing the other one works or it is the psu because I don’t have the right 8 pin connector or possibly something else???

The psu does not have an 8 pin connector for the mother board and I just plug the 4 pin into half of it. Not sure if this is a problem or not? It used to work fine.

if the mobo has an 8 pin connector, it needs 8 pins - you can buy adapters for your psu
sounds like theres also something wrong with your ram

what memtester are you running?

Memtest86 3.5 Release
http://www.memtest86.com/

Well the mobo had half a clip over the 8 pin connection. So I plugged the 4 pin into the open side.

Well the mobo had half a clip over the 8 pin connection. So I plugged the 4 pin into the open side.

Should be no probs.

Instability though, hmmm. Try 8800 with only 1GB RAM and see if that's a goer.

BANG!

if the mobo has an 8 pin connector, it needs 8 pins - you can buy adapters for your psu
sounds like theres also something wrong with your ram

where do you get your facts?

You can use the 4pin connector without issue. AFAIK these connectors are basically for the PCI-E so 8-pin connector is only necessary for high end PCI-E video cards... that or high end cpu's with multiple core processors.

one of the two, which im sure someone here will clarify :)

last edited by eP at 22:00:06 25/Feb/09

I now managed to boot with 1 stick and the 8800....

I am now more confused....

Check your Power Supply voltages. Perhaps the extra ram is chewing up that little bit more power then what it used to with both sticks and the 8800.

See if you can borrow another power supply and try that.

Well it worked for 2 months and I had the cpu overclocked and had multiple fans running inside.

I now have it at stock and disconnected 3 case fans so I am running with not much...

Pasted from hwmonitor with just one stick in. As wont boot with 2 sticks with 8800.

Winbond W83627DHG hardware monitor

Voltage sensor 0 1.12 Volts [0x8C] (CPU VCORE)
Voltage sensor 1 11.93 Volts [0xD6] (+12V)
Voltage sensor 2 3.33 Volts [0xD0] (AVCC)
Voltage sensor 3 3.30 Volts [0xCE] (+3.3V)
Voltage sensor 4 1.70 Volts [0xD5] (VIN1)
Voltage sensor 6 1.43 Volts [0xB3] (VIN3)

Which line should I be looking at?

last edited by jubs at 22:56:10 25/Feb/09

where do you get your facts?

You can use the 4pin connector without issue. AFAIK these connectors are basically for the PCI-E so 8-pin connector is only necessary for high end PCI-E video cards... that or high end cpu's with multiple core processors.

one of the two, which im sure someone here will clarify :)

Thats about it, it will only NEED the extra juice if you are running top of the line crap that consumes power like a black hole.

Regular systems will run fine with only the 4 pin plug



Also 550w will be plenty for that system.

Well I put the second stick of ram now in with the 8800 and now it boots.....

Ran 3dmark and it doesn't crash...

I do notice that when windows screen loads up there is a slight blur when it jumps out of the screen but is then normal straight away.

my understanding is high end video cards get their power directly from the psu, not via the bus
my 4870 has 2 x 6 pin connectors on it

the pins on the mother board are there because whatever cpu you're going to put in it is likely going to draw f***tonnes of power

last edited by tequila at 13:19:14 26/Feb/09

So you consider my psu is not cutting it?

I dunno I have the exact same PSU, they're pretty good
I think possibly the motherboard isn't getting the power it needs because you haven't got the pins plugged in

just like after the p4 boards they started using an extra 4 pins on the mother board to power the dual cores, the system would run without the 4 pins but not very well

now that they have 8 pins, i'd say the same applies

I am not 100% certain on this but I believe the extra 4 pin connector was for just for the top end CPUs - extreme edition quads which gobble power like candy.

The boards power is supplied by the ATX connector, new gen CPUs are fed by the 4 or 8 pins next to the socket. As I'm sure you remember, once upon a time there was only the ATX connector.

last edited by rubba-chikin at 13:48:06 26/Feb/09

I currently have the following problem with mine when I try to wake it up from sleep. I'm not saying this is your problem, but just use it to try play around with it. It's *really* wierd - you'll understand why in a sec.

Computer is in sleep mode.
Press power to bring it out of sleep (you'd think) - acutally just starts fans up. Computer never recovers from sleep.
Hold power button down to power off
Press power again - fans just turn on, still doesn't return from sleep.
Hold power button (again) to power off.
Press power - this time you get a POST beep, and the system returns from Hibernate.

In other words, I have to power it off *twice* before I can wake it up, it's bloody wierd, and extremely annoying.


Also, those extra 4 pins are just another ATX12 connector, so you can provide another phase of power when doing high-frequency/power overclocking etc and using high-draw systems.