Looking for advise on overclocking dual MSI R7870-2GD5T/OC graphics cards

Muddn2urgrave

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Oct 26, 2013
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Hi, I am currently working on overclocking my dual MSI R7870-2GD5T/OC cards.

I have a few questions I cant seem to find answers to.

First, what is a "safe" maximum voltage for the core on these?

I understand any overclock is not exactly safe and risky.

Also, I have been unable to find stats posted from anyone overclocking these cards.

I am curious what kind of results people are seeing.

So, getting into the thick of it. I am using MSI Afterburner version 3.0.0 Beta 15 for the overclocking.

I am Benchmarking and load testing with Heaven dx11 on all maximum settings.

Stock settings: Results:

Core voltage: 1219mv Avg FPS: 51.1
Power limit: +/_ 0 Score: 1288
Core Clock: 1050mhz Max Temp: 62 deg C
Memory: 1200mhz



Adjusted settings achieved: Results:

Core Voltage: 1231mv Avg FPS: 55.8
Power Limit: +5% Score: 1406
Core Clock: 1175mhz Max Temp: 67 deg C
Memory: 1333mhz


At that voltage and power limit I can benchmark the core at 1200 and memory at 1380. But it crashes after ten or fifteen minutes in a load test. so I backed it down. in the benchmark it gave me another 1.4 Fps.

I plan on working on raising the memory more tomorrow. Just running out of time today.

Do I dare push the power limit up? Do I dare raise the voltage a little more?

I would like to try and squeeze a little more out of them but I don't want paper weights either......

Thanks in advance for you comments. :)
 

Muddn2urgrave

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Oct 26, 2013
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Sorry that kinda ran together....


Stock settings:

Core voltage: 1219mv
Power limit: +/_ 0
Core Clock: 1050mhz
Memory: 1200mhz

Results:

AVG FPS 51.1
Score: 1288
Max Temp: 62 deg C


Adjusted settings achieved:

Core Voltage: 1231mv
Power Limit: +5%
Core Clock: 1175mhz
Memory: 1333mhz

Results:

Avg FPS: 55.8
Score: 1406
Max Temp: 67 deg C
 

Muddn2urgrave

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Oct 26, 2013
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Well. I found a thread elsewhere discussing overclocking of a reference msi HD 7870.

They were able to reach voltages of 1300mv.

They used a power limit of +20%. This power limit i was able to confirm on other threads as well.

1300mv sounds scary to me so i am going to leave my current voltage setting of 1231mv.

I will reset my memory speed to default and kimd of start over.

I will post my results later.

 

Muddn2urgrave

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Oct 26, 2013
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10,540
Ok. After spending two hours typing this up last night and then having the misfortune of hitting the wrong button and losing it all......... I will try this again. :)

After Eight or so hours of trial and error I learned a few things in this endeavor.

First off I was very surprised to learn how precise your voltage needs to be at a given core clock rate. I was unaware that too much voltage would decrease your output just as too little would. Once I figured this out things went quick and smooth.

Secondly, I was just as surprised to find that faster memory is not always better. I was able to clock the memory all the way to 1450mhz stable. But I actually got better results at a lower rate.

For anyone new to overclocking don't forget these two points. It will save you a ton of time later.

So, what I ended up doing was selecting a core voltage that I felt comfortable with. It turns out that the 1300mv that I mentioned in my earlier post is in fact the highest MSI Afterburner will allow you to go. Now I am just looking to milk a few more FPS out of my system not create really expensive paperweights. The stock voltage on my cards is 1219mv. I decided to go with 1238mv. It's a nice tweak but I think it's not very aggressive. Afterburner allows for increases of just over 6mv steps. If it doesn't like the number you punch in it adjusts them for you.
I went for a round number of 1240mv but got knocked back so I just rolled with it.

Next I began running MSI Kombuster. I used the Kmark open GL4 and PhysX Benchmark at 1920 x 1080. ( probably not the best choice but it did the job) At each run I increased the core clock by 25mhz until the gain turned into a loss. I then backed down to the prior clock setting and began increasing it by 5mhz. When I hit a loss I backed down to the prior setting and reran the program to confirm the number.

Clocking the memory speed was performed the same way. It worked out well for me.

After I completed my initial tests I decided to go back and rerun them. I ran three runs at AMD's reference clock, three at the cards stock o/c, and three at my overclock.

When this was completed I then ran three runs at each setting using Heaven. I have to say I love heaven. What a great benchmarking tool. If you haven't used it try it out. It never seems to get boring watching it either.

So here we go.

System specs,

i5 2500k o/c to 4.0ghz
MSI Z77A G45 Gaming mobo
16GB Corsair Xms3 DDR3 @ 1600mhz
120GB Kingston SSD
2TB Seagate Baracuda
2 X MSI R7870-2GD5T/OC


Benchmark tool: MSI Kombustor
Kmark Open GL4 and PhysX Preset at 1920 x 1080


Reference clock

core voltage: 1219mv
power limit: +/_0
core clock: 1000mhz
mem clock: 1200mhz

Score: X1991 @ 66 FPS



Stock o/c

core voltage: 1219mv
power limit: +/_0
core clock: 1050mhz
mem clock: 1200mhz


Score: X2009 @ 68 FPS



My o/c

core voltage: 1238mv
power limit: +20%
core clock: 1180mhz
mem clock: 1350mhz


Score: X2055 @ 75FPS




Benchmark Tool: Heaven
1920 x 1080 With 8xAA
Preset: custom
Quality: Ultra
Tessellation: Extreme


Reference clock


core voltage: 1219mv
power limit: +/_0
core clock: 1000mhz
mem clock: 1200mhz


Results: Avg. FPS: 49.8
Score: 1256
Min FPS: 18.6
Max FPS: 114.5



Stock o/c

core voltage: 1219mv
power limit: +/_0
core clock: 1050mhz
mem clock: 1200mhz


Results: Avg. FPS: 51.0
Score: 1284
Min FPS: 18.8
Max FPS: 117.0



My o/c

core voltage: 1238mv
power limit: +20%
core clock: 1180mhz
mem clock: 1350mhz


Results: Avg. FPS: 56.2
Score: 1471
Min FPS: 19.6
Max FPS: 130.4



Conclusions:

I am sure these cards will o/c more than I have gone. I did actually go a little higher at one point but was concerned. At this obtained overclock I do not receive a large increase in heat. My case has six fans. I now run about 69 deg as opposed to 64 deg under sustained load with the card fans locked at 45% I can live with that. When I ran higher the heat raised ALOT. I hit 79 deg with the card fans at 90% at one point. ( At a much higher voltage). Glad I was watching closely. :)

Real world gains???? Actually yes. The real gain here is in smoothness. I don't see a big frame rate increase in the real world. But the min frame rate is higher in game. It was never unplayable by any means but it just seems to make things more stable and somehow more clear.


If anyone has any comments or suggestions to what I have done please feel free to post them. I am always interested.