Quad-rail PSU (750w), 8800gtx, which rail for the GPU?

[Spoudazo]

So I have my 8800gtx hooked up, and it's been running fine for months, as long as I don't overclock it much. I'm thinking, perhaps if I hook it up to another rail, I can increase the OC. For a little bit after I bought the GPU, I had the GPU hooked up to two different rails, so it would crash if I ever OCd the GPU even the smallest amount.

Well, I hooked up both connections to the same rail, and now it OCs a little bit.

Now it will crash if the OC is about 620/935 while playing newer games, which I think is sorta dinky compared to some people's OC.

With my GPU just running at 905 on the memory (1810), I get artifacts after playing Crysis, because the memory is apparently artifacting. My case is a Coolermaster stacker, and it's setting right next to an A/C unit to help keep everything cool, as well as multiple fans in the case.

I'm just curious, if I should try another "rail," and also, how do I tell which "rail" the GPU is hooked to? Thanks.

Here are the specs of my PSU, It got a great review from Johnny Guru, and I also checked out several sites before buying this PSU.
http://www.newegg.com/Product/Product.asp?Item=N82E16817153038

Brand Thermaltake
Model W0116RU
Spec
Type Complies with ATX 12V 2.2 & EPS 12V version
Maximum Power 750W
Fans 14 cm Fan
SPEED: 1900 RPM (±10%)
DIMENSION: 140 X 140 X 25 mm
AIR FLOW: 82 CFM
TEMP. AUTO CONTROL
PFC Active
Main Connector 20+4Pin
+12V Rails 4
PCI-E Connectors 2 x 6Pin
NVIDIA SLI Support Yes
Modular Cabling Support Yes
Power Good Signal 100-500ms
Hold-up Time 16ms min.
Efficiency up to 85%
Over Voltage Protection Yes
Overload Protection Yes
Input Voltage 100 - 240 V
Input Frequency Range 47 - 63 Hz
Input Current 10A @ 115V, 5A @ 230V
Output +3.3@30A,+5V@28A,+12V1@18A,+12V2@18A,+12V3@18A,+ 12V4@18A,[email protected],+5VSB@3A
MTBF >120,000 hours
Approvals CE, CB, TUV, FCC, UL, CUL, and BSMI certified

 

[JamesXP]

It has 4 12V rails.


I'm guessing

One 12V rail for CPU connector
One 12V rail for perephials
Two 12V rails for GFX cards.(2x6/8pin PCI-e)

 

[ViperJohn]

So I have my 8800gtx hooked up, and it's been running fine for months, as long as I don't overclock it much. I'm thinking, perhaps if I hook it up to another rail, I can increase the OC. For a little bit after I bought the GPU, I had the GPU hooked up to two different rails, so it would crash if I ever OCd the GPU even the smallest amount.

Well, I hooked up both connections to the same rail, and now it OCs a little bit.

Now it will crash if the OC is about 620/935 while playing newer games, which I think is sorta dinky compared to some people's OC.

With my GPU just running at 905 on the memory (1810), I get artifacts after playing Crysis, because the memory is apparently artifacting. My case is a Coolermaster stacker, and it's setting right next to an A/C unit to help keep everything cool, as well as multiple fans in the case.

I'm just curious, if I should try another "rail," and also, how do I tell which "rail" the GPU is hooked to? Thanks.

This is fairly standard. Since the PS is ATX 2.0 / 2.1 compliant:

12V1 will feed the 24 pin ATX connector, SATA power and 4 Pin Molex connectors.

12V2 will feed the MB's CPU 4 or 8 pin aux connector (and nothing else).

12V3 will power one 6 pin PCIe aux power connector

12V4 will power the other 6 pin PCIe aux power connector.

Some PS builder's will put the molex connectors on 12V3 and/or 12V4.

You GTX's OC issues are not power related with that PS. It is either running to warm to OC well
or, if it is a standard clocked card, it is simply a poor OC'er.

Viper

 

[jason4207]

I have the eVGS 320 Superclock, and the most I can get is 621/1620/918, so don't feel too bad.