yet another 8600M GT owner

[Guest alliao]

Hi all,

My 8600M GT is a ddr2. I open my laptop up for best heat dissipation. The temperature read out from GPU-Z/Hardware Monitor/RivaTuner are the same, and with an additional fan on top it never exceeds 78 degrees Celsius.

I'm trying to overclock it a bit, from stock to around 570MHz (linked with shader) and 470MHz for memory, as you can see it's not a "huge" overclock like some others in this forum have posted.

However, it's not very stable. The temperature stays around there, but from time to time after 45mins to 70mins of continuous gaming it'll be stuck in low power 3D speed, which is some 275MHz if I recall correctly.

What is happening here?

I've tried turning off powermizer, and used NVPMManagerUni to turn off the overheat protection but it made no noticeable difference.

I have to recommend NVPM Manager for instant apply function, as it reloads the driver it allows me to regain my full 3D speed without a reboot. However obviously one can't reboot "while" gaming, so it's rather frustration playing at 15fps when it usually goes flying around 50-60fps.

Any ideas?

(a pic of my laptop/desktop :))

[Guest BOOP]

hard to see from the picture, but is your laptop lifted so that there is space below it? (that's where the air enters)

also, you could try flashing the video bios (highly not recommended =/ ) so you can up the voltage maybe (not reommended either).

[Guest Robbo]

Hi, I think I agree with the previous poster. Your temperatures seem fine, and you many only be able to overclock more by upping the voltage on the GPU. As the previous poster said, this probably isn't recommended!

Just as a quick note on you opening up your laptop. I notice the fan is exposed. Like this won't the air that is sucked in from underneath just blow straight out of the top now it has no cover on rather than being forced through the cooling fins, because the air will take the path of least resistance which would now be straight out the top of you laptop where you've removed the cover? Wouldn't that make the cooling worse? Have you got hot air still coming out of the back of the laptop (where the cooling fins are located)? If you don't then your cooling may be worse with the mod you have done? You could also try a laptop cooler - I use the Zalman NC-2000 which I would recommend. If you can get your GPU to run cooler you might be able to overclock with more stability as well.

[Guest alliao]

Hi, I think I agree with the previous poster. Your temperatures seem fine, and you many only be able to overclock more by upping the voltage on the GPU. As the previous poster said, this probably isn't recommended!

Just as a quick note on you opening up your laptop. I notice the fan is exposed. Like this won't the air that is sucked in from underneath just blow straight out of the top now it has no cover on rather than being forced through the cooling fins, because the air will take the path of least resistance which would now be straight out the top of you laptop where you've removed the cover? Wouldn't that make the cooling worse? Have you got hot air still coming out of the back of the laptop (where the cooling fins are located)? If you don't then your cooling may be worse with the mod you have done? You could also try a laptop cooler - I use the Zalman NC-2000 which I would recommend. If you can get your GPU to run cooler you might be able to overclock with more stability as well.

The fans' blades are actually straight.. so all it does is push air "around it" and yes the hot air still do come out of the vent on the left hand side. I keep it open so when it gets too hot, i can put a fan directly on top of it :)

Unfortunately my gpu bios is wrapped inside the system's BIOS, and i don't know enough to screw around the bios...

I guess what i want to know is what makes the gpu clock down after extended use? I used to think only temperature will affect it.. but now it seems rather arbitrary.

[Guest Robbo]

The fans' blades are actually straight.. so all it does is push air "around it" and yes the hot air still do come out of the vent on the left hand side. I keep it open so when it gets too hot, i can put a fan directly on top of it :)

Unfortunately my gpu bios is wrapped inside the system's BIOS, and i don't know enough to screw around the bios...

I guess what i want to know is what makes the gpu clock down after extended use? I used to think only temperature will affect it.. but now it seems rather arbitrary.

Right, so it looks like you've got the cooling side of things sorted! I'm not sure why it's downclocking, but have you tried lowering the memory clock, as the DDR2 8600M GT's don't overclock so well on their memory. Maybe try lowering the memory clock 20Mhz or so & see if you have the same problem. If you don't have the problem anymore, then why not go ahead and see if you can squeeze a few more Mhz or overclock on the core & shader! I've got an M1530 (Dell), and the 8600M GT GDDR3 version, which I've overclocked for regular gaming to 692/1550/1000 (stock being 475/950/700), so hopefully you'll be lucky enough to get a few more Mhz out of the core & shader.

[Guest alliao]

Right, so it looks like you've got the cooling side of things sorted! I'm not sure why it's downclocking, but have you tried lowering the memory clock, as the DDR2 8600M GT's don't overclock so well on their memory. Maybe try lowering the memory clock 20Mhz or so & see if you have the same problem. If you don't have the problem anymore, then why not go ahead and see if you can squeeze a few more Mhz or overclock on the core & shader! I've got an M1530 (Dell), and the 8600M GT GDDR3 version, which I've overclocked for regular gaming to 692/1550/1000 (stock being 475/950/700), so hopefully you'll be lucky enough to get a few more Mhz out of the core & shader.

hmm interesting idea, i guess i have some inferior complex as owner of ddr2 :) always thinking memory's too slow and want to keep it up.

i can overclock to 570/1425/400 and it does give me quite a nice boost, however still downclocks after an hour or so.. quite odd = =

[Guest Robbo]

hmm interesting idea, i guess i have some inferior complex as owner of ddr2 :) always thinking memory's too slow and want to keep it up.

i can overclock to 570/1425/400 and it does give me quite a nice boost, however still downclocks after an hour or so.. quite odd = =

Hi, I think I'm out of ideas now! Although one last idea from me. Considering that you're overclocking this creates a larger power draw on the power adapter (increase in Watts), and I've heard that you can get strange behaviour if the power supply is not rated to supply the increased power required. You could try undervolting your CPU using RMClock (if you google RMClock you'll be able to find out where to download & how to use it). By undervolting your CPU your overall system will use less power, and also run cooler. I've managed to undervolt my T7250 from 1.175V down to 0.975V, but results will vary from each individual unit to the next. Because you're using the same heat pipe for both the CPU & the GPU, then by undervolting you should notice not only a decrease in CPU temperature, but also a decrease in GPU temperature. Undervolting doesn't slow down the CPU, just makes it run using less Watts.

You don't need to google RMClock, I've found the link for you:

http://forum.notebookreview.com/hardware-components-aftermarket-upgrades/235824-undervolting-guide.html

[Guest alliao]

i already do rmclock to reduce temperature, however i think ur ram suggestion's right on the money! i opened up my laptop and saw that there were no contact between heatsink and ram modules, so after extended use ram probably went corrupt and thus it automatically downclocks, after 2hrs or so left 4 dead 2, i think it's safe to say you have found the real culprit!

Thanks Robbo! good catch, next time i'll try and accept my gpu for what it is :) cheers!

[Guest Robbo]

i already do rmclock to reduce temperature, however i think ur ram suggestion's right on the money! i opened up my laptop and saw that there were no contact between heatsink and ram modules, so after extended use ram probably went corrupt and thus it automatically downclocks, after 2hrs or so left 4 dead 2, i think it's safe to say you have found the real culprit!

Thanks Robbo! good catch, next time i'll try and accept my gpu for what it is :) cheers!

Hi, no problem, good to hear that you got to the bottom of it. Squeezing the most performance out of what we have is the best thing to do. Means you don't have to upgrade so soon! Take it easy! :)

[Guest cash]

Right, so it looks like you've got the cooling side of things sorted! I'm not sure why it's downclocking, but have you tried lowering the memory clock, as the DDR2 8600M GT's don't overclock so well on their memory. Maybe try lowering the memory clock 20Mhz or so & see if you have the same problem. If you don't have the problem anymore, then why not go ahead and see if you can squeeze a few more Mhz or overclock on the core & shader! I've got an M1530 (Dell), and the 8600M GT GDDR3 version, which I've overclocked for regular gaming to 692/1550/1000 (stock being 475/950/700), so hopefully you'll be lucky enough to get a few more Mhz out of the core & shader.

can you post you best 3d mark?? or just the shader 3 score?? thats a massive oc, i'm wondering how much benefit you get??

[Robbo the Second]

can you post you best 3d mark?? or just the shader 3 score?? thats a massive oc, i'm wondering how much benefit you get??

Hi, I'm a member now, hence the slight change in username! Since I posted previously I've increased the OC some more, and this time I know I'm at the absolute limit, but it is 100% stable. I'm now at 700 core / 1700 shader / 1000 memory. It's the shader that's really impressed me. That's a 79% increase in clock on the shader - nuts! (And apparently shaders are becoming more important in the modern games, so that's a bonus). Temperatures are only a degree or 2 warmer with that increased OC in comparison to the last OC I posted.

You asked me about the specifice of my 3DMark06 results. Here they are, (as a side note the results have been further increased by 'overclocking' my CPU to 'Dual IDA' mode using a free program called Throttlestop - I started a topic on this website devoted to that (that topic is in the news section under 'If you can't overlcock your Core 2 Duo try this').

Total 3DMark06 score (1280x800 monitor res) = 7029

Shader 2.0 score = 3172

Shader 3.0 score = 2963

CPU score = 1909 (was 1700 before the OC of the CPU using ThrottleStop).

The stock 3DMark06 score when I bought the laptop in early 2008 was 4527. So that's a 55% increase in 3DMark06 result!

I think I'v been very lucky to have received a GPU chip in this computer that is able to OC to literally insane levels without overdoing it on the temperature. I've yet to see anyone with a bigger OC on this chip, I've been very fortunate. Everyone will get different results, it's the luck of the draw!

I've been running my GPU OC'd since June 2008, and no problems so far. Fingers crossed for the GPU living on under this overclock! (I believe it will live on for a while now still, because the temperatures are always under 85 degrees centigrade, and mostly hovering at 79 degrees centigrade when gaming.)

Edited September 5, 2010 by Robbo the Second