(update--final GPU speed is 225MHz, only 10% reduction)
A picture is worth a thousand words (running at 1.36vcore). The card.
NEW:
Voltage mod close-up
Open case view (what looks like another fan in the PSU is just an emptied fan frame for structural support)
GeForce4 Titanium is NVIDIA's fastest videocard yet--and unfortunately the hottest-running, which is why all of them ship with whiny high-speed fans. Now, I really don't like fans--I prefer peace and quiet. My entire system including PSU is currently cooled by a single 80mm Panaflo fan; and I managed to pull this off with an AthlonXP and now a GeForce4 Ti4200!
I got the Gainward Ti4200 64MB, because 4200 is the cheapest and coolest-running GeForce4. My initial steps, which I have already described here, include obtaining an Alpha PAL6035 copper/aluminum heatsink and Arctic Silver epoxy. I threw away the factory HSF, then lapped the GPU and Alpha surface, then glued on the Alpha. Here is a photo of the modified videocard.
While my fanless GF4 ran just fine with this modification, its temperatures were alarming: with case closed, they ranged from 80 to a scalding 84.0 Celsius under heavy load, with case open! At these temps, the lifetime of the videocard would be significantly shortened. By comparison, my GeForce2 MX (which came without even a heatsink) would get up to 82.0C with case closed. I assume this was a normal temperature for it. I decided to reduce GeForce4's temps well below 80C.
How did I reduce the GeForce4 temps? By reducing the power it consumes, which is achieved by a highly effective combination of reducing GPU core voltage and slighlty underclocking the card. First, about the voltage reduction.
Xbitlabs has a terrific article on how to increase GeForce4 voltage for extreme overclocking. I had to do the opposite--reduce the voltage. My Gainward 4200 uses SC1102 voltage regulator chips (found on the backside of the board); the GPU regulator is the one near the metal mounting bracket. Xbitlabs posts its schematic here. The voltage passed to the GPU equals 1.265*(1+R8/R7) volts, so Xbitlabs added another resistor to R7 in parallel to reduce total resistance, thus increasing the R8/R7 ratio and the resulting voltage. I needed to do the opposite, so I had to find R8 and add another resistor in parallel to it.
First I realised (from the diagram) that Pin 11 was directly connected to one side of R8; I just had to find where its other side was. I bought myself a multimeter and used it to measure the resistors on the board near the SC1102 chip (I assure you, I've never done anything like this before! blahblah99 helped me a lot advising what to do here.) Ultimately, I found R8. Here is the SC1102 chip, and here are R8's two contacts. I also measured, by connecting to SC1102's Ground pin and point B on R8, that the default GPU voltage is 1.64V.
Now I bought some resistors, and, starting from the highest-rated one (100 ohms) soldered its ends to points A and B in the second picture. Lo and behold, the GPU voltage was really decreased!! 100-ohm resistor brought it down to 1.43V; I replaced that with a 68-ohm resistor, which yielded 1.39V, and finally a 47-ohm resistor which gave 1.36Vcore! Since power is proportional to voltage squared, doing this reduced power output by 31%!
The other measure was to underclock the GPU. This would reduce power proportionally to the clockspeed, and (more importantly) make sure the GPU would remain stable at the reduced voltage. From past underclocking experience, I reduced GPU clockspeed to 210MHz, which is almost proportional to the voltage decrease. This is 84% of the default 250MHz, which is still much better performance than any GeForce3 or GeForce4MX out there! Keep in mind that memory is still running at default 513MHz, so bandwidth-limited applications won't see any change.
I then used NVFlash and NVIDIA BIOS editor to make 210MHz the "true" default clockspeed, and made this awesome startup message.
How did my changes pay off? Well, right now my case is closed again, and after heavy load I'm only getting 72.0Celsius, which is 10C lower than the GeForce2MX using its "normal" passive cooling! With case open, we're talking mid-60's. I can attest that undervolting made a VERY noticeable reduction in heat, that you can feel by touching the heatsink. Altogether, assuming my 4200 originally produced 20 watts of heat, now it would be only ~11.6watts, or only 58% of the original!
This proves that the fanless GeForce4 is possible, for anyone determined enough to build one!
Leo
A picture is worth a thousand words (running at 1.36vcore). The card.
NEW:
Voltage mod close-up
Open case view (what looks like another fan in the PSU is just an emptied fan frame for structural support)
GeForce4 Titanium is NVIDIA's fastest videocard yet--and unfortunately the hottest-running, which is why all of them ship with whiny high-speed fans. Now, I really don't like fans--I prefer peace and quiet. My entire system including PSU is currently cooled by a single 80mm Panaflo fan; and I managed to pull this off with an AthlonXP and now a GeForce4 Ti4200!
I got the Gainward Ti4200 64MB, because 4200 is the cheapest and coolest-running GeForce4. My initial steps, which I have already described here, include obtaining an Alpha PAL6035 copper/aluminum heatsink and Arctic Silver epoxy. I threw away the factory HSF, then lapped the GPU and Alpha surface, then glued on the Alpha. Here is a photo of the modified videocard.
While my fanless GF4 ran just fine with this modification, its temperatures were alarming: with case closed, they ranged from 80 to a scalding 84.0 Celsius under heavy load, with case open! At these temps, the lifetime of the videocard would be significantly shortened. By comparison, my GeForce2 MX (which came without even a heatsink) would get up to 82.0C with case closed. I assume this was a normal temperature for it. I decided to reduce GeForce4's temps well below 80C.
How did I reduce the GeForce4 temps? By reducing the power it consumes, which is achieved by a highly effective combination of reducing GPU core voltage and slighlty underclocking the card. First, about the voltage reduction.
Xbitlabs has a terrific article on how to increase GeForce4 voltage for extreme overclocking. I had to do the opposite--reduce the voltage. My Gainward 4200 uses SC1102 voltage regulator chips (found on the backside of the board); the GPU regulator is the one near the metal mounting bracket. Xbitlabs posts its schematic here. The voltage passed to the GPU equals 1.265*(1+R8/R7) volts, so Xbitlabs added another resistor to R7 in parallel to reduce total resistance, thus increasing the R8/R7 ratio and the resulting voltage. I needed to do the opposite, so I had to find R8 and add another resistor in parallel to it.
First I realised (from the diagram) that Pin 11 was directly connected to one side of R8; I just had to find where its other side was. I bought myself a multimeter and used it to measure the resistors on the board near the SC1102 chip (I assure you, I've never done anything like this before! blahblah99 helped me a lot advising what to do here.) Ultimately, I found R8. Here is the SC1102 chip, and here are R8's two contacts. I also measured, by connecting to SC1102's Ground pin and point B on R8, that the default GPU voltage is 1.64V.
Now I bought some resistors, and, starting from the highest-rated one (100 ohms) soldered its ends to points A and B in the second picture. Lo and behold, the GPU voltage was really decreased!! 100-ohm resistor brought it down to 1.43V; I replaced that with a 68-ohm resistor, which yielded 1.39V, and finally a 47-ohm resistor which gave 1.36Vcore! Since power is proportional to voltage squared, doing this reduced power output by 31%!
The other measure was to underclock the GPU. This would reduce power proportionally to the clockspeed, and (more importantly) make sure the GPU would remain stable at the reduced voltage. From past underclocking experience, I reduced GPU clockspeed to 210MHz, which is almost proportional to the voltage decrease. This is 84% of the default 250MHz, which is still much better performance than any GeForce3 or GeForce4MX out there! Keep in mind that memory is still running at default 513MHz, so bandwidth-limited applications won't see any change.
I then used NVFlash and NVIDIA BIOS editor to make 210MHz the "true" default clockspeed, and made this awesome startup message.
How did my changes pay off? Well, right now my case is closed again, and after heavy load I'm only getting 72.0Celsius, which is 10C lower than the GeForce2MX using its "normal" passive cooling! With case open, we're talking mid-60's. I can attest that undervolting made a VERY noticeable reduction in heat, that you can feel by touching the heatsink. Altogether, assuming my 4200 originally produced 20 watts of heat, now it would be only ~11.6watts, or only 58% of the original!
This proves that the fanless GeForce4 is possible, for anyone determined enough to build one!
Leo