EVGA Nvidia GTX 780 SC ACX - Memory overclocking has absolutely no effect on FPS

[RedShores]

Hey guys! I have an EVGA Nvidia Geforce GTX 780 SC (Superclocked) ACX (Active Cooling Xtreme) video card. I have been overclocking it using software called EVGA Precision X. I have been benchmarking the overclock with a program called Unigine Heaven Benchmark 4.0 DirectX 11. On Windows 7 64-Bit with 4GB (2 x 2GB) of RAM. With latest Nvidia drivers as of May 18 2015 which is version 352.86. My power Supply is an Antec Basiq Plus at 550w.

With no overclock whatsoever, on a resolution of 1920x1200 (16:10) with Anti-Aliasing turned off, I get 100.8 fps.

When overclocking the Core Clock of the GPU, I was able to get up to +150 mhz with an overvoltage of 1237mv as the highest it would go and still be stable. This gave me an fps of 108.8 on Unigine. Precision X reports my GPU Core clock to be 1241 mhz after the +150 mhz overclock, but a utility called GPU-Z reports it as 1117 mhz. I don't know why there is a difference between the 2 programs, or which one is correct. Does anyone know which program is more trustworthy in reporting this?

The major problem I am having today is that when I attempt to overclock the memory, I get literally no difference in performance at all. I have even gone as high as +700 mhz on the memory with absolutely no extra FPS on Unigine.

The Unigine benchmark DOES report the memory as having increased (with no overclock it shows 3004 mhz, then with +700 it shows 3704 mhz in Unigine)

I have tried the following things that did NOT help:
-Turning KBOOST on and off.
-Trying various voltages, even zero extra voltage.
-Leaving NVidia display driver service on services.msc running or disabled
-Changing fan speeds
-Trying another overclocking utility, MSI Afterburner.

I even tried putting the memory at +2000 mhz which immediately crashed the computer. So it DOES seem to be taking effect, just not actually increasing performance at all. Nothing I do seems to actually make the memory overclock have any effect on the performance of FPS in Unigine.

At this point, I want to mention my previous card which was a MSI Nvidia Geforce GTX 660 Ti with 2GB of GDDR5 Vram. Using the exact same computer and same software, I was able to get very good performance increases on FPS while overclocking the memory on that card.

So here are the possible reasons this could be happening as far as I can guess:

-The Nvidia Geforce 700 series use a microarchitecture called Kepler Refresh. Perhaps there is something different within this microarchitecture that handles how the memory behaves compared to the original Kepler from the 600 series. So that overclocking the memory would only have an effect on things like Anti-Aliasing or extra eye candy like that. Stuff that I had turned off during the benchmark.

-My motherboard is an older model that is still using PCI-Express 2.0 x16. So it is not PCI-Express 3.0 x16 which came out in November 2010. But I have read a few articles online that suggest there no significant difference between these 2 generations of PCI-Express. So I don't think this is the problem. The exact model of the motherboard is GIGABYTE GA-P45T-ES3G LGA 775 Intel P45 ATX Intel Motherboard North Bridge Intel P45 South Bridge Intel ICH10 3gb/s sata 2

-I'm still using an Intel E8400 Wolfdale Core 2 Duo CPU from January 2008. It still uses the Front Side Bus method of talking to the rest of the motherboard. And it uses the old socket type of LGA 775. I'm wondering if this old processor is causing the problems? But my older video card overclocked the memory just fine so I don't think this is the case.

-The Nvidia Geforce GTX 780 I'm using has 3GB of GDDR5 VRam. The older GTX 660 ti I was using only had 2GB of GDDR5 VRam. Perhaps something about having that extra 1GB of ram is related to why the memory overclock doesn't do anything? That maybe the resolution of 1920x1200 is not enough to push the memory? To have an advantage with an overclock?

The GTX 780 I'm currently using seems to work just fine in every other way. Games play fine, videos look good, no odd noises or smells. Color is great, nothing else seems to be strange. The performance of the card in every other aspect is good enough to make me think this issue is by design and not by any defect.

I tried searching with google for anyone else having this problem but could not find anything about this issue so it seems I'm probably unique for the moment.

I'm waiting for Intel Skylake to come out in August or September of this year to upgrade my processor, I suppose at that point I'll see if the motherboard or processor have anything to do with this. But if I had to guess they arn't related to the problem.

So I want to ask the community what they think the problem is with the memory overclocking having no effect on the GTX 780. I would greatly appreciate any information provided by people more knowledgeable than myself. Again thanks for reading my post.

 

[C0RR0SIVE]

I wanna say CPU and RAM is limiting you in the long-term... PP should be around to give better advice... I just know your CPU is on the side of needing an upgrade before your GPU needed it...

 

[PP Mguire]

Hey guys! I have an EVGA Nvidia Geforce GTX 780 SC (Superclocked) ACX (Active Cooling Xtreme) video card. I have been overclocking it using software called EVGA Precision X. I have been benchmarking the overclock with a program called Unigine Heaven Benchmark 4.0 DirectX 11. On Windows 7 64-Bit with 4GB (2 x 2GB) of RAM. With latest Nvidia drivers as of May 18 2015 which is version 352.86. My power Supply is an Antec Basiq Plus at 550w.

With no overclock whatsoever, on a resolution of 1920x1200 (16:10) with Anti-Aliasing turned off, I get 100.8 fps.

When overclocking the Core Clock of the GPU, I was able to get up to +150 mhz with an overvoltage of 1237mv as the highest it would go and still be stable. This gave me an fps of 108.8 on Unigine. Precision X reports my GPU Core clock to be 1241 mhz after the +150 mhz overclock, but a utility called GPU-Z reports it as 1117 mhz. I don't know why there is a difference between the 2 programs, or which one is correct. Does anyone know which program is more trustworthy in reporting this?

If you're not using a second monitor to watch the clocks during benchmarks then more than likely you're not seeing the full boost clock in GPU-Z.

The major problem I am having today is that when I attempt to overclock the memory, I get literally no difference in performance at all. I have even gone as high as +700 mhz on the memory with absolutely no extra FPS on Unigine.

The Unigine benchmark DOES report the memory as having increased (with no overclock it shows 3004 mhz, then with +700 it shows 3704 mhz in Unigine)

I have tried the following things that did NOT help:
-Turning KBOOST on and off.
-Trying various voltages, even zero extra voltage.
-Leaving NVidia display driver service on services.msc running or disabled
-Changing fan speeds
-Trying another overclocking utility, MSI Afterburner.

I even tried putting the memory at +2000 mhz which immediately crashed the computer. So it DOES seem to be taking effect, just not actually increasing performance at all. Nothing I do seems to actually make the memory overclock have any effect on the performance of FPS in Unigine.

Unigine isn't a heavily VRAM extensive benchmark. It scales more to CPU and GPU Core clock increases than anything. Also, the 780 is a 384-bit bus width card so it's not exactly lacking in memory bandwidth. Get a 980 and increase the VRAM by 440, you'll see a difference because it's 256-bit. Also if you ran 3DMark 13 (latest) you might see a small increase, but the rest of your system is holding you back more than VRAM.

At this point, I want to mention my previous card which was a MSI Nvidia Geforce GTX 660 Ti with 2GB of GDDR5 Vram. Using the exact same computer and same software, I was able to get very good performance increases on FPS while overclocking the memory on that card.

That's because the 660ti is a 192-bit bus width card. Much less memory bandwidth than the 780.

So here are the possible reasons this could be happening as far as I can guess:

-The Nvidia Geforce 700 series use a microarchitecture called Kepler Refresh. Perhaps there is something different within this microarchitecture that handles how the memory behaves compared to the original Kepler from the 600 series. So that overclocking the memory would only have an effect on things like Anti-Aliasing or extra eye candy like that. Stuff that I had turned off during the benchmark.

600 and 700 series (minus 750ti) are all Kepler, no refresh. The only difference being is the 670/680/770 use the GK204 chip (midrange) and the 780/780ti/Titan/Titan Black use the GK210 chip which is the high end. GK210 uses 384-bit memory bus to achieve a higher memory bandwidth and the 700 series started with a 7GHz VRAM clock speed by default which is higher than the 680.

-My motherboard is an older model that is still using PCI-Express 2.0 x16. So it is not PCI-Express 3.0 x16 which came out in November 2010. But I have read a few articles online that suggest there no significant difference between these 2 generations of PCI-Express. So I don't think this is the problem. The exact model of the motherboard is GIGABYTE GA-P45T-ES3G LGA 775 Intel P45 ATX Intel Motherboard North Bridge Intel P45 South Bridge Intel ICH10 3gb/s sata 2

-I'm still using an Intel E8400 Wolfdale Core 2 Duo CPU from January 2008. It still uses the Front Side Bus method of talking to the rest of the motherboard. And it uses the old socket type of LGA 775. I'm wondering if this old processor is causing the problems? But my older video card overclocked the memory just fine so I don't think this is the case.

Your setup is holding back both cards. You only saw an increase on the 660ti due to the above reasoning I mentioned before.

-The Nvidia Geforce GTX 780 I'm using has 3GB of GDDR5 VRam. The older GTX 660 ti I was using only had 2GB of GDDR5 VRam. Perhaps something about having that extra 1GB of ram is related to why the memory overclock doesn't do anything? That maybe the resolution of 1920x1200 is not enough to push the memory? To have an advantage with an overclock?

See above.

The GTX 780 I'm currently using seems to work just fine in every other way. Games play fine, videos look good, no odd noises or smells. Color is great, nothing else seems to be strange. The performance of the card in every other aspect is good enough to make me think this issue is by design and not by any defect.

I tried searching with google for anyone else having this problem but could not find anything about this issue so it seems I'm probably unique for the moment.

I'm waiting for Intel Skylake to come out in August or September of this year to upgrade my processor, I suppose at that point I'll see if the motherboard or processor have anything to do with this. But if I had to guess they arn't related to the problem.

So I want to ask the community what they think the problem is with the memory overclocking having no effect on the GTX 780. I would greatly appreciate any information provided by people more knowledgeable than myself. Again thanks for reading my post.

Bolded answers to specific parts of the post.

If you read my article you'll see that your old processor is holding you back quite a bit actually. In games specifically you'll see a huge difference and increase in performance compared to your old C2D. To your original memory deal, it's all about memory bandwidth. Like I explained before your old card had a narrower bus width so the bandwidth on the 780 is pretty much double that. Once tossing a 780 into your old rig it pretty much makes everything else a big bottleneck. When you get your new Skylake setup you'll notice that it's not so much about VRAM or VRAM bandwidth, but more so GPU core clock speeds. Won't even need to OC the CPU at all.