Overclocking my ASUS DirectCU 5850

[Slayer697]

My ASUS DirectCU 5850 finally came in today and I've spent the better part of the day overclocking it. Some of my results are expected, and others I just don't understand. I thought I'd post my findings here with the hopes that more experienced forum members might have some additional insight that might help me achieve a higher and more stable overclock. I've been using the following guide to help me overclock my GPU:

http://www.overclock.net/ati/633816-how-overclock-your-ati-gpu.html

I wasn't quite able to reach my personal goal of a 1050MHz overclock, but I was able to run 1000MHz stable in GPUTool.

Overclocking GPU

Highest stable GPU Clock: 1000MHz @ 1.25V (used ASUS SmartDoctor to adjust voltage for this one)

Overclocking Memory

Highest stable memory clock: 1300MHz

Overclocking GPU and Memory

Highest stable GPU/memory combined clocks: 980MHz clock with 1300MHz memory at 1.218V

Other Notes

In addition to using GPUTool, I ran a substantial number of benchmarks using Furmark with Xtreme Burning Mode, Displacement mapping, Post FX, and 8xMSAA sampling. Unfortunately, what GPUTool thinks is stable is not even remotely okay with Furmark. Attempts to test stability in Furmark with my highest stable GPU and Memory overclock ended with my GPU reaching a temp of 104C before the drivers failed. GPUTool on the other hand never peaked above 82C. Preliminary testing with Furmark has my highest stable overclock so far at 950 with a voltage of 1.718V. This is my second time writing this post as my last test with Furmark resulted in a driver crash my system did not recover from.

Increasing voltage didn't help me reach a much higher overclock. I was able to get to 930Mhz clock on stock settings, and grab another 50MHz with the next .05, but any attempts to go over 1000MHz resulted in a driver reset. Voltages between 1.25 and 1.3 all behaved the same. I didn't go higher just to be safe.

 

[Truhls]

Most cases ive seen of stable OC's for 5850's are just over 900 to the 950 range range with what seems to be about 10-15% hitting the 1000 hit. I think you are sitting pretty well considering.

Personally i had so many problems with asus smartdocter it wasnt even funny. If you crashed during a game ( which you will more then likely, cus furmark will not cause a crash with all the settings on and in extreme burning but a 3 year old game will ) smartdoctor likes to reset everything you did on a reboot. Yes i know you can set it to boot up at the last settings but honestly, it just seems like a shitty OC tool overall.

 

[wolfram23]

Well first of all 1300mhz GPU RAM is retardedly good. That's amazing. I'd like to see some benchmarks of that. Mine get's artifacts over 1220.

The voltage control is only for core, you can't modify the ram volts.

My absolute maximum OC has been 985/1200 at 1.225V. I tried up to about 1.35V for 1000 core but it's just not stable. I've never used that GPU tool but FurMark is a good stability test for sure.

 

[Rustyy117]

thats an impressive memory speed, just remember that even if the RAM isn't stable it won't show error's (Artifacts) as you would expect.

Good core clock/voltage too.

 

[ashkaji]

Im considering getting the same 5850 just so I have the option to overclock. Im interested to see in detail how much difference OCing makes (to performance and heat). I dont think I'll overclock at first, but if a game comes along that needs that extra umff to play nicely, Id probably do it then.

 

[Slayer697]

thats an impressive memory speed, just remember that even if the RAM isn't stable it won't show error's (Artifacts) as you would expect.

Good core clock/voltage too.

What kind of errors should I expect to see if the RAM isn't stable? I'm a bit shocked that I didn't see any artifacts at 1300, and I know with CCC I can probably get that number even higher if I really want to. Is it possible that overclocking my processor will help with stability of the system (driver reboots) at 1000MHz core clock?

Im considering getting the same 5850 just so I have the option to overclock. Im interested to see in detail how much difference OCing makes (to performance and heat). I dont think I'll overclock at first, but if a game comes along that needs that extra umff to play nicely, Id probably do it then.

I definitely recommend the card. Even though I didn't hit my own target goal, I have a solid stable overclock that's about 30% more than stock. I'll post some temperature and benchmark information once I've got a final overclock.

 

[Rustyy117]

Basically GDDR5 memory can detect error's (caused by instability) and re-send the data again until it succeeds without error, the resending of data takes time, and so will loose you performance. Obviously the more unstable the memory the more times it will have to re-send data.

This explains it better than me....

GDDR5 memory controllers can perform basic error detection on both reads and writes by implementing a CRC-8 hash function. With this feature enabled, for each 64-bit data burst an 8-bit cyclic redundancy check hash (CRC-8) is transmitted via a set of four dedicated EDC pins. This CRC is then used to check the contents of the data burst, to determine whether any errors were introduced into the data burst during transmission.

The specific CRC function used in GDDR5 can detect 1-bit and 2-bit errors with 100% accuracy, with that accuracy falling with additional erroneous bits. This is due to the fact that the CRC function used can generate collisions, which means that the CRC of an erroneous data burst could match the proper CRC in an unlikely situation. But as the odds decrease for additional errors, the vast majority of errors should be limited to 1-bit and 2-bit errors.

Should an error be found, the GDDR5 controller will request a retransmission of the faulty data burst, and it will keep doing this until the data burst finally goes through correctly. A retransmission request is also used to re-train the GDDR5 link (once again taking advantage of fast link re-training) to correct any potential link problems brought about by changing environmental conditions. Note that this does not involve changing the clock speed of the GDDR5 (i.e. it does not step down in speed); rather it’s merely reinitializing the link. If the errors are due the bus being outright unable to perfectly handle the requested clock speed, errors will continue to happen and be caught. Keep this in mind as it will be important when we get to overclocking.

So your RAM as 1300Mhz could be effectively slower than if it was running at 1200Mhz

When I was testing for my max RAM overclock on my 5850, I used the resident evil 5 benchmark to see when I would start to loss performance due to unstable RAM. Here is what I found.

Resident Evil 5 maxed out 1280 x 720 DX10

1000/1200Mhz 141.7FPS

1000/1250Mhz 138.7FPS

1000/1150Mhz 141.2FPS

So this told me that my 5850's RAM at 1250Mhz was unstable as I got a deduction in FPS compared to 1200Mhz.

Hope that helped.

 

[ashkaji]

Resident Evil 5 maxed out 1280 x 720 DX10

1000/1200Mhz 141.7FPS

1000/1250Mhz 138.7FPS

1000/1150Mhz 141.2FPS

So this told me that my 5850's RAM at 1250Mhz was unstable as I got a deduction in FPS compared to 1200Mhz.

Hope that helped.

I wouldent have thought about that at all! +1 Great info!

 

[OvrClkr]

My DirectCU maxes out at 1060/1310 1.28v but since I see no perfromance gain I just leave it at 1000/1250 1.22v with load temps of 68c max unless running kombustor extreme burn-in. Here are some screenies :

IDLE @ 1.2v :

IDLE @ 1.25v :

Quick Bench @ 1.25v :

I cannot locate my extreme-burn-in screenie but it topped out at 79c after 10 minutes @ 1050/1300 1.26v.

Here is a Heaven Bench @ 975/1250 :

I also re-pasted the cooler with MX-2 and saw an improvement in temps by -2/-3c. The paste that comes with the DirectCu is garbage, when I removed the cooler I found out that the paste was not spread evenly and in-turn gave me an idle temp of 36-37c.

 

[wolfram23]

omgitzfatal: Great info!!! Wow that explains a lot... I was trying to do just a little overclock tweaking so I had the RAM at I think it was 1213 but the fps in Crysis benchmark were worse! I'll have to keep working on it, maybe try 1 mhz increments from 1200 to 1210 and see where it appears to top out.

As to general overclocking tips, I investigated the effects of having 4xAA on in FurMark on gpu core and memory speeds. With AA turned off, only core speed would increase FPS, but with 4xAA, the only thing that increased FPS was memory speed while core didn't make the slightest impact on average FPS. It did slightly help the min by maybe 1-2.
x-axis: core. y-axis: fps. z-axis memory

 

[Slayer697]

When I was testing for my max RAM overclock on my 5850, I used the resident evil 5 benchmark to see when I would start to loss performance due to unstable RAM.

Is there a reason you chose RE5 to test this? Would any other benchmark be sufficient or only specific ones?

My DirectCU maxes out at 1060/1310 1.28v but since I see no perfromance gain I just leave it at 1000/1250 1.22v with load temps of 68c max unless running kombustor extreme burn-in.

...

I also re-pasted the cooler with MX-2 and saw an improvement in temps by -2/-3c. The paste that comes with the DirectCu is garbage, when I removed the cooler I found out that the paste was not spread evenly and in-turn gave me an idle temp of 36-37c.

Do you actually run your card on a regular basis with 1000/1250 1.22V? I would love to run mine like that if I could get it stable at 1000MHz consistently. I've thought about repasting my own cooler, but considering I just got the thing, I'm a little worried about voiding the warranty. I was also planning on selling it in a year or so to help with an upgrade to a better card.

x-axis: core. y-axis: fps. z-axis memory
[url]http://i746.photobucket.com/albums/xx103/Wolfram23/th_memandcorespeedvsfps.png[/URL]

Try as I might I just can't seem to understand this graph. It looks as though your best performance is at lower memory and lower clocks with 1000MHz memory speed being the best setting since it gives 50 FPS across the board. How is this graph supposed to be interpreted?

 

[wolfram23]

Sorry Slayer. Here's the whole post on it with explanations etc
http://www.tomshardware.com/forum/259144-29-antialiasing-core-doesn-matter-memory-baby

I just got bored when I was doing it and didn't feel like running another 5 tests when I could already see a clear trend so the graph is a bit screwy lol.

 

[Slayer697]

Sorry Slayer. Here's the whole post on it with explanations etc
http://www.tomshardware.com/forum/259144-29-antialiasing-core-doesn-matter-memory-baby

I just got bored when I was doing it and didn't feel like running another 5 tests when I could already see a clear trend so the graph is a bit screwy lol.

Okay, now I understand it. I didn't realize that the graph looked like that because it was missing data points. That's an interesting point and one I'll definitely keep in mind.

Another couple things I've noticed:

1. When I have afterburner on, the card no longer downclocks when dealing with less graphics intensive processing. Is there a way around this?
2. ASUS SmartDoctor and Afterburner both start with the system and I haven't been able to find out how to disable this functionality. Is uninstalling them the only way?

 

[OvrClkr]

Do you actually run your card on a regular basis with 1000/1250 1.22V? I would love to run mine like that if I could get it stable at 1000MHz consistently. I've thought about repasting my own cooler, but considering I just got the thing, I'm a little worried about voiding the warranty. I was also planning on selling it in a year or so to help with an upgrade to a better card.

I run it at 1000/1250 1.22v when I play BF2 which is everyday after work, if I am not playing I switch OC profiles and go down to 950/1175 1.8v and it stays relatively cool considering its "over-volted".

What driver are you using? What are your load temps when stressing @ 100%? Why sell when you can cross-fire?

 

[OvrClkr]

Okay, now I understand it. I didn't realize that the graph looked like that because it was missing data points. That's an interesting point and one I'll definitely keep in mind.

Another couple things I've noticed:

1. When I have afterburner on, the card no longer downclocks when dealing with less graphics intensive processing. Is there a way around this?
2. ASUS SmartDoctor and Afterburner both start with the system and I haven't been able to find out how to disable this functionality. Is uninstalling them the only way?

I have both programs running in the background and have no issues whatsoever, as long as you click on the "apply overclocking at startup" on AB you should be good to go. If you do not want AB to start then un-check the "apply overclocking at startup" and your done. You need doctor in order for the card to work properly.

 

[Slayer697]

I run it at 1000/1250 1.22v when I play BF2 which is everyday after work, if I am not playing I switch OC profiles and go down to 950/1175 1.8v and it stays relatively cool considering its "over-volted".

What driver are you using? What are your load temps when stressing @ 100%? Why sell when you can cross-fire?

I'm using Catalyst 10.5. What app do you want you want me to stress test with? I want to sell because I probably won't be able to sell cross-fired 5850s in two years, but I might be able to sell the one 5850 in a year. It really depends on the cost of upgrade and whether or not keeping the 5850 will be more useful to me.

I have both programs running in the background and have no issues whatsoever, as long as you click on the "apply overclocking at startup" on AB you should be good to go. If you do not want AB to start then un-check the "apply overclocking at startup" and your done. You need doctor in order for the card to work properly.

What do I need to keep doctor open for? I don't mind afterburner, but doctor keeps giving me a message every time I start my computer about some other program I didn't install. I don't want to uninstall it, but I don't want it to open up on startup.

 

[wolfram23]

Okay, now I understand it. I didn't realize that the graph looked like that because it was missing data points. That's an interesting point and one I'll definitely keep in mind.

Another couple things I've noticed:

1. When I have afterburner on, the card no longer downclocks when dealing with less graphics intensive processing. Is there a way around this?
2. ASUS SmartDoctor and Afterburner both start with the system and I haven't been able to find out how to disable this functionality. Is uninstalling them the only way?

If you run an overclock using Afterburner it won't downclock it. If you set the speeds back to default tho, then they'll drop down at idle. The way you get around it is to BIOS flash your video card so that it's 3D mode is whatever your overclock is and then it'll still run normal downclocks - if you use RBE you can custom set clocks and volts and all that stuff. You can even make it so that in ATI Overdrive you can OC to 1100/1300 if you want - not that those would necessarily work lol.

 

[Rustyy117]

It doesn't have to be resdient evil 5 benchmark, it can be any 3d benchmark, aslong as the scores don't vary to much, for example, Dirt 2's benchmark varies alot from 1 run to another (using the same settings and overclock)

Something like Crysis benchmark would work well...

Nice info Wolfram23 Ialso found that increasing the memory speed helped my minimum FPS

Crysis All very high DX10 1920 x 1080 noAA

1000/1150 Min: 26.54 Max: 45.91 Avg: 40.98

1000/1200 Min: 30.81 Max: 46.54 Avg: 41.365

Thats over a 4 FPS gain in minimum FPS! Peachy

 

[Rustyy117]

Oh and slayer I've done what Wolfram23 said with RBE, if you want to do it then I can help you out if you want.

 

[Slayer697]

Oh and slayer I've done what Wolfram23 said with RBE, if you want to do it then I can help you out if you want.

Will doing this void my warranty? Will it help me get a more stable overall overclock?

 

[Rustyy117]

Yes I think it does void your warranty, but overclocking does that for you already...

Yes it will help you get more stable overclocks because you can change the 3D voltage, but the main reason I did it is so that my card down clocked it self when in 2D mode and I also didn't have to mess around with programs and profiles.

To test my Core overclock I used Crysis benchmark tool for about 2 hours, stress testing the memory is harder as there is no visual indication as to whether or not your memory is unstable (E.g. Artifacts) So I used Resdient Evil 5 for that, although I could have used Crysis, but I got bored of looking at Crysis...

When It comes to finding your highest stable memory frequency run a benchmark at stock memory speed, note the results and then up your memory speed by 50Mhz and run the same benchmark again, do this process until your score gets worse at which point you've found where your memory is unstable, then reduce your memory speed by 50 Mhz and your done.

You could say "well my memory is stable at 1250Mhz, but not at 1300Mhz so I'm going to run the benchmark again at 1260Mhz and see if its stable". That way you'll find the exact point where your memory is unstable.

EDIT: Just to say that you can use pretty much any 3D app or game to test the Core stability E.G... Furmark, ATi tray tools, 3Dmark, game benchmarks, just playing a game.... ETC

 

[wolfram23]

Just to add on, as you probably know from the link about the AA and memory speed, you can run FurMark with 4x or 8xAA to test memory as well. I reflashed my cards now to 885/1220 and so far so good, although I had a crash after several hours in STALKER yesterday but I'm not sure it was the video card... gotta keep testing.

 

[OvrClkr]

I'm using Catalyst 10.5. What app do you want you want me to stress test with? I want to sell because I probably won't be able to sell cross-fired 5850s in two years, but I might be able to sell the one 5850 in a year. It really depends on the cost of upgrade and whether or not keeping the 5850 will be more useful to me.



What do I need to keep doctor open for? I don't mind afterburner, but doctor keeps giving me a message every time I start my computer about some other program I didn't install. I don't want to uninstall it, but I don't want it to open up on startup.

You need to make sure you have both Doctor and Gamer OSD installed if you want the card to work properly.

Use furmark or kombustor (Afterburner) to stress your GPU.

 

[OvrClkr]

If you run an overclock using Afterburner it won't downclock it. If you set the speeds back to default tho, then they'll drop down at idle. The way you get around it is to BIOS flash your video card so that it's 3D mode is whatever your overclock is and then it'll still run normal downclocks - if you use RBE you can custom set clocks and volts and all that stuff. You can even make it so that in ATI Overdrive you can OC to 1100/1300 if you want - not that those would necessarily work lol.

Of course it will down-clock, but in order for this to occur he needs to first make sure that he has the correct programs installed in order for the GPU to work properly. Here is an example of me using AB to overclock the card, you can see how it is running at 157/300 :

 

[Slayer697]

You need to make sure you have both Doctor and Gamer OSD installed if you want the card to work properly.

I'm still not sure I understand why I need doctor installed. I'm able to adjust voltage frequency with Afterburner anyway. Doctor is overall a pretty awful program and I'd like to get rid of it unless you can explain why you say I need it installed.