Computer locking up after upgrading water cooling. Need Help Troubleshooting

[stewie0056]

So Just installed a new water cooling loop in my PC and now it's locking up randomly. I think I've narrowed it down but I would like some other opinions.

I think It's either the Northbridge getting too hot or the power supply is not powerful enough.

Okay here's the spec's

Asus crosshair v formula motherboard
AMD FX 8150 (not over clocked)
G.Skill Ripjaws z series Ram 4x4gb DDR3 2133
AMD radeon hd 6770 1gb graphics (x2 in crossfire)
Thermaltake TR2 RX 750watt PSU
2 WD green hard drives
1 WD Black hard drive
1 OCZ SSD


Originally I was using a Thermaltake water 2.0 pro closed loop liquid cooler to cool the CPU but it wasn't enough

I now installed a Swiftech Apogee XL water block on the CPU and a pump/reservoir combo using the Swiftech MCP655 PWM. I have the radiator mounted outside the case with two 120 fans in push pull config. No leaks anywhere.

Okay so when I start the computer after being off for a while (several hours) it boots fine and works great but but after running for a 30 minutes of just sitting at the desktop under no load it locks up (screen image freezes and no response to hard buttons) then I have to hard reset it. When I try turning it back on it tries booting but doesn't even get to the bios screen before it freezes. The Q-LED section on the motherboard shows the CPU error led light on. If i turn it off wait few minutes and restart now it shows DRAM LED instead. If i keep repeating this on and off enough I find it will just displays the led wherever it just happens to lock up while booting. So that offers no help.

These are the temps of my system while first booting after being off for several hours
30c cpu
25c water temp
35c graphics
32c built in motherboard temp sensor
33c infrared on Northbridge heatsink

Temps when system locks up
33c cpu
28c water
40c graphics
33c built in motherboard temp sensor
40c infrared on Northbridge heatsink

Not sure if where the generic motherboard temperature sensor I am displayed is located, so i took my infrared thermometer reading on the Northbridge heatsink. I tried to hold the same angle and distance for both reading

The only way I can get my system to boot and stay on is to take the side off and put a Window box fan pointing in and on high setting. I also have the water pump running to a separate power supply unit and I am only using only one graphics card. The other is completely removed from the system.

using various online power supply calculators i came up with
~480 watts estimated max consumption with 1 graphics card on system
~600 watts estimated max consumption with two graphics in crossfire on system

I figure since i'm using of my 2/3 of my power supply that shouldn't be the problem.
Also looking at other people's Northbridge temp online the say they are okay to run hot like 60c average so i don't think that's the issue either.

i would like to try these one at a time to narrow it down but first i want to here your suggestions so i don't damage anything permanently

Anyone have any better ideas of what's going on? I'm baffled what's going on. Never had this probably for the past couple years while I used the Thermaltake closed loop and everything was running hotter than it is now.

Thanks in advance!

[stewie0056]

okay i see what your saying Z, good catch.
For some reason i was thinking it would not exceed its rating, but i know better than that and wasn't thinking clearly.
A motor can act as a dead short if stalled so having bad flow can cause this pump to draw a lot more power.
though i have to say when i felt the motor it was actual quite cool.

i have previously moved the pump's power connection to a separate 500 watt power supply unit and i still suffered from the computer freezing, though it did take longer than if i still had the pump connected to the 750.

I am starting to agree on the power supply being the issue but, i do not have a spare high wattage PSU laying around and none of my friends have one to borrow so it looks like i'm going to have to order one. Is 860 watts good enough or should i go over 1000 watts?

This weekend i plan on tearing out the new water cooling and reseating the cpu.
Also i have plans to hook the 750 watt psu up to a some dummy loads and check to see if it is still performing correctly

Are there any other test you would like me perform in the meantime?

[kkn]

well if you are getting a new PSU, the range from 850W and upwards is what i would recommend.
that way you will have some headroom too.