Nvidia's Throttling kicking in from speed not heat? (GTX260)

[slouth2000]

Hello everyone! I discovered this forum a few days ago, and thought I'd make a post about a weird issue I had with my new GTX260.


Ok so I bought a GTX 260 from Evga, its supposed to have 192 Shaders, but GPU-Z says that it has 216. Whether I actually do have 216 shaders or not would be nice to know, although that's not the reason I'm posting today.


For future reference my GTX 260's stock speeds are 576 Core / 1242 Shader / 999 Memory.


A few days ago I installed RivaTuner, saw that my GPU's fan was at 40%, so I upped it to 100%. I then opened AtiTools and ran the 3d cube. My temps maxed out in the low 50's. I of course proceeded to overclock the card. Also I didn't run Atitool for more than 5 mins each time I upped the speed. I wasn't checking for long term stability yet.

I was able to get the card to around 750 / 1620 / 1215 before I saw a single artifact in Atitool (and when it made that one it made another every few seconds). The problem comes from the fact that I was only able to even test that speed once. Every other time I've tried within 2 secs the card reverts to its low power 3D settings and refuses to go higher until I reboot my PC (then it works until I try that OC again). Nothing I do can get it back above 400 / 800 / 300. All the settings in Atitool, rivatuner, and GPU-Z show my correct overclock, the card just refuses to go into performance 3D mode. It'll swap back and forth between Standard 2D and Low Power 3D mode like it does normally, it just won't go all the way to full 3D mode, even in games. (lol@crysis in Low power 3d)

That sounds an awfully lot like throttling, but I thought Nvidia throttled off heat. The GPU never got above 55C. It will immediately throttle on cold boot to applying those settings when its around like 40C

Oh and if I revert the OC to default timings (576/1242/999), it still won't go into Performance 3D. Its a permanent "throttle" until I reboot.


My question is whats causing that?


I have a 680W PSU and only 1 video card and HDD, my PCI slots are empty also. It could be a voltage problem on the GPU but I thought I'd get major instability or artifacting if that was the case, not actually being locked entirely out of performance 3D mode (still kinda new to OC'ing though). My temps also never got above 60C during the entire OC process.

Computer Specs:
Vista Ultimate 64-bit
Core 2 Duo E6600@ 2.4 Ghz
G.skill 2GB DD2-800
ASUS P5Q PRO mobo
Seagate 1.5TB HDD
Nvidia GTX 260 (180.84 beta)
random cheap DVD Burner.
680W PSU

Rivatuner = v2.21, Atitool = 0.27b4, GPU-Z = 0.3.0

Anyway I have it stable at 700 / 1500 / 1215, haven't really pushed it higher because I've been wanting to use the card not benchmark for hours. Which is still a pretty hefty OC

 

[Steven-1979]

Whats your other graphics card temps looking like? GPU / VRM / RAM

 

[slouth2000]

I turned on my overclock of 702 / 1512 / 1215 and then ran the Atitool Artifact test for 20 minutes. The Core Temp (GPU) rose to 55C after 5 minutes or so and stayed at 55C for the next 15 minutes. The Ambient Temp was 44 - 45C in rivatuner. Atitool calls it the temperature of the temp chip. Both programs agreed on GPU / Ambient temps. The card Idles at around 37C (GPU), 31C (ambient).

The built in temp probe could be wrong, but before my OC on stock settings (incl stock fan speed). The temps would hit 60 - 65C, so it can go past 55C.

I don't have a temperature probe to measure the temps all across the board, but the heatsink on the GPU also touches all the ram chips and wraps around the entire card. So if the GPU is only 55C I don't think the memory would be much if any higher.

Plus overclocking the GPU + Shaders is what throttled me in the first place. I haven't pushed the memory past 1215 yet.

 

[grunion]

Hello everyone! I discovered this forum a few days ago, and thought I'd make a post about a weird issue I had with my new GTX260.


Ok so I bought a GTX 260 from Evga, its supposed to have 192 Shaders, but GPU-Z says that it has 216. Whether I actually do have 216 shaders or not would be nice to know, although that's not the reason I'm posting today.


For future reference my GTX 260's stock speeds are 576 Core / 1242 Shader / 999 Memory.


A few days ago I installed RivaTuner, saw that my GPU's fan was at 40%, so I upped it to 100%. I then opened AtiTools and ran the 3d cube. My temps maxed out in the low 50's. I of course proceeded to overclock the card. Also I didn't run Atitool for more than 5 mins each time I upped the speed. I wasn't checking for long term stability yet.

I was able to get the card to around 750 / 1620 / 1215 before I saw a single artifact in Atitool (and when it made that one it made another every few seconds). The problem comes from the fact that I was only able to even test that speed once. Every other time I've tried within 2 secs the card reverts to its low power 3D settings and refuses to go higher until I reboot my PC (then it works until I try that OC again). Nothing I do can get it back above 400 / 800 / 300. All the settings in Atitool, rivatuner, and GPU-Z show my correct overclock, the card just refuses to go into performance 3D mode. It'll swap back and forth between Standard 2D and Low Power 3D mode like it does normally, it just won't go all the way to full 3D mode, even in games. (lol@crysis in Low power 3d)

That sounds an awfully lot like throttling, but I thought Nvidia throttled off heat. The GPU never got above 55C. It will immediately throttle on cold boot to applying those settings when its around like 40C

Oh and if I revert the OC to default timings (576/1242/999), it still won't go into Performance 3D. Its a permanent "throttle" until I reboot.


My question is whats causing that?


I have a 680W PSU and only 1 video card and HDD, my PCI slots are empty also. It could be a voltage problem on the GPU but I thought I'd get major instability or artifacting if that was the case, not actually being locked entirely out of performance 3D mode (still kinda new to OC'ing though). My temps also never got above 60C during the entire OC process.

Computer Specs:
Vista Ultimate 64-bit
Core 2 Duo E6600@ 2.4 Ghz
G.skill 2GB DD2-800
ASUS P5Q PRO mobo
Seagate 1.5TB HDD
Nvidia GTX 260 (180.84 beta)
random cheap DVD Burner.
680W PSU

Rivatuner = v2.21, Atitool = 0.27b4, GPU-Z = 0.3.0

Anyway I have it stable at 700 / 1500 / 1215, haven't really pushed it higher because I've been wanting to use the card not benchmark for hours. Which is still a pretty hefty OC

You must maintain > 2:1 ratio on the shader/core speeds.
< 2:1 you already know what happens.
These are actual speeds, not the speed you request.
This is due to the clock generators divider, been this way since the G80.
Use the Rivatuner hardware monitor graph to monitor the actual speeds.

You say that you are stable at 700/1500, well 1500 shader is actually 1512mhz, the next shader strap will be at 1540 with the actual speed being 1566.

 

[slouth2000]

Ah, I had no Idea I needed to keep >2:1 ratio.

Could someone possibly elaborate a little more on the ratio's?

Aince my current clock is 702 / 1512, then it seems like its below a 2:1 ratio already. Same with the stock settings of 576 / 1242. In both cases the GPU speed is 50 - 100 mhz less (when doubled) than the shader speed. So wouldn't that be < 2:1 ratio? Am I looking at it wrong?

 

[grunion]

Ah, I had no Idea I needed to keep >2:1 ratio.

Could someone possibly elaborate a little more on the ratio's?

Aince my current clock is 702 / 1512, then it seems like its below a 2:1 ratio already. Same with the stock settings of 576 / 1242. In both cases the GPU speed is 50 - 100 mhz less (when doubled) than the shader speed. So wouldn't that be < 2:1 ratio? Am I looking at it wrong?

1512/702=2.15
1242/576=2.15