Geoffrey's 7300GT worklog - Page 7

geoffrey · 24th August 2007, 08:24

42°C idle, 50°C load
the core is too small to make good use of all six heatpipes.

Didn't have any problem to fit this thing inside my case. Temps were very bad though when I powered on the system, increasing mounting pressure decreased the core temperature around 7°C idle and +10°C load.

Voltmod will be done this weekend, I'll try to use my father's scope to investigate a possible third hardware modification.

Massman · 24th August 2007, 08:36

Is it a work-in-progress or van you specify what extra mod we're talking about

geoffrey · 24th August 2007, 08:39

it's been too long to remember what the mod exactly could be, I'll update you once I dived back into it

geoffrey · 25th August 2007, 18:10

The APW7067 has a frequency control pin. The switching frequency of the PWM circuit can be altered by changing the resistance between this pin and ground, here is a how-to picture:

I mentioned the standard resistor to measure around 100kOhm, actually it is around 110kOhm. If you replace the onboard resistor, keep in mind that you always have measured around 110kOhm between pin 2 and ground before powering your system. Lower resistance at pin 2 gives higher switching frequency, here is a graph:

In PWM circuit we have a central unit, the APM7067 for example, which triggers two power mosfets X00 000 times per second. Those mosfets are connected between ground and 12V, by changing the trigger signal we are allowed to change the circuit's output voltage. PWM stands for Pulse Width Modulation, this means that the circuit's output voltage is set by altering the switching pulse width, not the switching frequency. What exactly does this mod do? I have no idea, but I did try it and this is what I measured:

Before frequency mod: VGPU = 1,304V
After frequency mod: VGPU = 1,304V

I changed the resistance between pin 2 and ground from 110kOhm to 90kOhm, this didn't have any impact on the GPU core voltage. Therefore, this tweak doesn't look to be very useful, maybe it increases the change to hit higher frequency's once the card is voltmodded, I'll try to find out as soon as possible.

jmke · 25th August 2007, 19:21

although no "real" results yet, impressive results

also pics of the modded card?

Massman · 25th August 2007, 19:45

Impressive Geoffrey

geoffrey · 26th August 2007, 20:49

Quote:

Originally Posted by geoffrey

HR-03 Plus heatsink, clocks 670/860

Nature 3D Mark 2001: 180,4
Nature 3D Mark 2003: 73,1

card unmoddified

Funny, I can bench at those clocks with passive cooling

HR-03 Plus is not the best cooling solution though, without a fan you can feel the temperature difference between the heatpipes in the center and those at the edge. Going to voltmod my card in a few moments, picture(s) comming up J

geoffrey · 26th August 2007, 23:33

Upped the GPU core voltage to 1,5V, I'm able to bench at 750MHz now and score 200FPS in 3D Mark 2001 Nature test while my memory is still on default voltage (860MHz). There is more left at 1,5V, Rivatuner's clock setting bar was pulled completely to the right side and I was to lazy to edit the power users settings

My GPU core temperature is terrible, 77°C load, mounting is not ideal, when pressing the heatsink's base onto the GPU by hand the load temperature dropped with 7°C!
I might be using something different then this when hunting for the 1st place

PS: it seems that voltage fluctuates a bit more when increasing the PWM clock, I'm at 80kOhm now.

geoffrey · 27th August 2007, 15:43

AC riple measured on GPU core voltage level:

Adding two 1000uF capacitors didn't change the riple.

Picture of my card in action:

27th August 2007, 16:31

Are temps better now , i hade 53 stressed ( vijzen waren zeer hard aangedraaid ik kon koelblok niet meer verschuiven )

24th August 2007, 08:24	#61
geoffrey [M] Reviewer Join Date: Nov 2004 Posts: 4,127	42°C idle, 50°C load the core is too small to make good use of all six heatpipes. Didn't have any problem to fit this thing inside my case. Temps were very bad though when I powered on the system, increasing mounting pressure decreased the core temperature around 7°C idle and +10°C load. Voltmod will be done this weekend, I'll try to use my father's scope to investigate a possible third hardware modification. Last edited by jmke : 24th August 2007 at 08:39. Reason: there we go degreasing again ;)

25th August 2007, 18:10	#64
geoffrey [M] Reviewer Join Date: Nov 2004 Posts: 4,127	The APW7067 has a frequency control pin. The switching frequency of the PWM circuit can be altered by changing the resistance between this pin and ground, here is a how-to picture: I mentioned the standard resistor to measure around 100kOhm, actually it is around 110kOhm. If you replace the onboard resistor, keep in mind that you always have measured around 110kOhm between pin 2 and ground before powering your system. Lower resistance at pin 2 gives higher switching frequency, here is a graph: In PWM circuit we have a central unit, the APM7067 for example, which triggers two power mosfets X00 000 times per second. Those mosfets are connected between ground and 12V, by changing the trigger signal we are allowed to change the circuit's output voltage. PWM stands for Pulse Width Modulation, this means that the circuit's output voltage is set by altering the switching pulse width, not the switching frequency. What exactly does this mod do? I have no idea, but I did try it and this is what I measured: Before frequency mod: VGPU = 1,304V After frequency mod: VGPU = 1,304V I changed the resistance between pin 2 and ground from 110kOhm to 90kOhm, this didn't have any impact on the GPU core voltage. Therefore, this tweak doesn't look to be very useful, maybe it increases the change to hit higher frequency's once the card is voltmodded, I'll try to find out as soon as possible. Attached Thumbnails

25th August 2007, 19:21	#65
jmke Madshrimp Join Date: May 2002 Location: 7090/Belgium Posts: 79,021	although no "real" results yet, impressive results also pics of the modded card? __________________

26th August 2007, 23:33	#68
geoffrey [M] Reviewer Join Date: Nov 2004 Posts: 4,127	Upped the GPU core voltage to 1,5V, I'm able to bench at 750MHz now and score 200FPS in 3D Mark 2001 Nature test while my memory is still on default voltage (860MHz). There is more left at 1,5V, Rivatuner's clock setting bar was pulled completely to the right side and I was to lazy to edit the power users settings My GPU core temperature is terrible, 77°C load, mounting is not ideal, when pressing the heatsink's base onto the GPU by hand the load temperature dropped with 7°C! I might be using something different then this when hunting for the 1st place PS: it seems that voltage fluctuates a bit more when increasing the PWM clock, I'm at 80kOhm now. Last edited by geoffrey : 26th August 2007 at 23:35.

27th August 2007, 15:43	#69
geoffrey [M] Reviewer Join Date: Nov 2004 Posts: 4,127	AC riple measured on GPU core voltage level: Adding two 1000uF capacitors didn't change the riple. Picture of my card in action: Attached Thumbnails

24th August 2007, 08:36	#62
Massman [M] Reviewer Join Date: Nov 2004 Location: Waregem Posts: 6,466	Is it a work-in-progress or van you specify what extra mod we're talking about

24th August 2007, 08:39	#63
geoffrey [M] Reviewer Join Date: Nov 2004 Posts: 4,127	it's been too long to remember what the mod exactly could be, I'll update you once I dived back into it

25th August 2007, 19:45	#66
Massman [M] Reviewer Join Date: Nov 2004 Location: Waregem Posts: 6,466	Impressive Geoffrey

27th August 2007, 16:31	#70
Cranox Posts: n/a	Are temps better now , i hade 53 stressed ( vijzen waren zeer hard aangedraaid ik kon koelblok niet meer verschuiven )

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