Corsair VX550 fan replacement...

O

Ogilvy

2[H]4U
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Oct 30, 2007
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Hi. I recently replaced the fan in my Corsair VX550 because the fan speed was winding up and down under load. I know this perfectly normal (albeit annoying), as I have 8800 GTs in SLI and the peak load for the whole system is probably well over 450w.

I also know I voided the warranty.


The problem is, both my 8800GTs were idling at about 45c and 41c. The cards are at stock speeds.

After the fan replacement, the master card is now idling @ 58c. (the second card is idling about 51c). (Even if I rotate the cards and the PCI-e connectors, the master card is always 58c.) The power supply is not creating more heat..it is cool to the touch. The load temps for the cards are still normal, though. Everything else appears to be running normally.


I was wondering if there was some kind of internal regulator that would be thrown off by not having a fan plugged into the two-pin slot on the circuit board inside the power supply. (the replacement fan is powered externally via molex.)

Are the cards drawing more juice at idle than they should now?
 
Temps going up after a power supply change....I doubt the cards are pulling more power now that they were earlier.

Here are some ideas:

1. Case airflow has changed for the worse. Somehow the power supply fan is causing a hot spot to develop in the case. I kind of favor this issue. what do you think?

2. The software used for the videocard temp readings is not accurate. Is there another method for you to check the card temperatures like one of those heat sensing laser guns?

3. The power supply is somehow causing a bad reading at the cards. (A long shot).
 
The replacement fan may not be as powerful as the fan that the PSU came with.

What case are you using?
 
Hopefully a stupid question but. .. Is the fan blowing the correct way?
 
The fan is blowing the right way. There is little to no heat coming off the power supply...the replacement fan is working fine. (I didn't replace the power supply, remember...just the fan.)

Case ambient temp. has remained the same, also. Even if I have a side fan blowing directly on the cards, the idle temps. are the same.


What's also a bit odd is, the 8800 GTs have different coolers on them, so the idle and load temps. for each had been different before the PS replacement fan. Even if I switched the cards, making either of them the master, you could tell by the temps. which card was which.


Now, no matter which card is the display master, it idles at 57-58c. and the secondary card is 52-53c.


Actually, I'm thinking this might be healthier...as it might seem that both cards are running more in sync with each other, though the idle temps aren't particularly healthy.


I don't know what to make of it...
 
Likely the original fan spinning faster kept more airflow going through the case and kept your cards cooler. The ambient case temp might be measured somewhere where airflow doesn't matter and might not change too much, but the change in airflow from the faster fan to the slower fan can make a large difference in temps on things that were in that path.
 
bcwang said:
Likely the original fan spinning faster kept more airflow going through the case and kept your cards cooler. The ambient case temp might be measured somewhere where airflow doesn't matter and might not change too much, but the change in airflow from the faster fan to the slower fan can make a large difference in temps on things that were in that path.
Click to expand...



Nah the power supply is at the bottom of the case with the fan facing down. But you were on the right track. My case airflow changed, but it had nothing to do with the power supply.


I just assumed that because my case temps. were the same, my video card temps. should be the same.

I just learned a lesson on how important airflow is.
 
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