• 12V rails: Which is which?!
    10 replies, posted
So I'm having a bit of a problem. My system tends to go into total lock-down when running something highly GPU intensive, and I've narrowed down the pausible causes: 1) Power MOSFETs on the GPU get pretty damn hot under load, but I can assume this is normal and is an easy fix (bigger heatsink!) 2) The PSU isn't supplying enough jiggawatts to my GPU. So, the PSU I have is a GreatPower X14S4P4 700W with 4 +12V rails at 18A each, which should be more than plenty to power my GTX285 (considering the "minimum amperage" ratings take into account ALL the amperage available), but there's a problem: I don't know if I'm actually plugging my GPU into just 1 rail! So my question is, how can I determine which connections are coming out of which rail without ripping into this thing?
Consult your user's manual? What is the manufacturer and motherboard type and processor?
The manual contains no such info I'm afraid. Motherboard is an Asus M2N-SLi and the CPU is an Athlon FX-62, no over-clocks.
Just try another connector. One of two things will happen: 1) It will still crash and make no difference. 2) It won't crash and you'll be happy. Also post the part number and temperature (When crashing) of the MOSFET.
Unfortunately I can't get a temperature reading from the MOSFET, GPU-Z doesn't have a read-out for it. (if anyone knows of a program that does I'd like to know) And it turns out I can't change the connectors around as much as I'd like, there's only two PCI-E cable connections and ONLY those two, the other two are permanently wired in. (no success using that one either)
Get ASUS drivers working on your PC, then download [url]http://support.asus.com/download/download.aspx?model=M2N-E%20SLI&SLanguage=en-us[/url] ASUS PC Probe II. It will tell you all the voltage information you need.
I already have PC Probe. Let me explain this better. My PSU has 4 +12V rails. Still with me? Good. It's also modular. Hey, hey, over here. Ignore that pigeon for a sec, alright? Good. I have no idea what connectors are connected to which rail. Got it now?
Wellp, the damn thing did it again twice since my last post. Once when running ATi Tool's 3D View over-night (according to GPU-Z the temp only got to 53C so that further tells me that my GPU heatsink is not to blame, but perhaps the VRM sinks are) And again today while playing Team Fortress 2 (not sure of the temps on this one, didn't leave GPU-Z running but it rarely gets over 55C when playing) So now I'm doing something out of desperation to try and get to the bottom of this mystery: I'm trying to put a different heatsink on the VRM chips and see if THAT doesn't help any. Materials are limited as I'm unemployed, but I've got two old 686-era aluminum heatsinks lying around that I can cut to fit, the problem is putting the resultant sink on and KEEPING it on. Superglue seems to be a poor choice as thermal cycling appears to break most super-glue bonds so I'm looking into cheap local alternatives...
The multiple rail PSUs were intended to help with multi-gpu setups, but end up being less robust than ones with a single, high voltage rail. I suggest you exchange your current one for a Corsair/Seasonic/PC Power and cooling one.
If the manual doesn't say which is which I don't know of any way to find out short of taking it apart. Just swap them around and hope you get lucky.
[QUOTE=Generic Monk;19997712]The multiple rail PSUs were intended to help with multi-gpu setups, but end up being less robust than ones with a single, high voltage rail. I suggest you exchange your current one for a Corsair/Seasonic/PC Power and cooling one.[/QUOTE] I'd love to but I'm umemployed and going to college. :saddowns: Plus I'm starting to think that if it were the PSU, it'd do it alot quicker, whereas it seems to be affected by the temperature. (it was fairly warm in my room today when TF2 and, consequentially, my computer took a shit on me) BUT, I was able to find some old RAM sinks with thermal tape on them, and they look like they might do a better job than the current VRM heatsink will. (considering the original VRM heatsink didn't even cover all the VRM chips, I had to cover the rest with RAM sinks anyway) Update: IT VERKS! Sorry for wasting y'alls time.
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