Did I get a terrible GPU?

[Biggles_]

Hi guys,

I've been trying to overclock my Sapphire HD7850 OC Edition without much success. I have been using this thread: http://forums.overclockers.co.uk/showthread.php?t=18389760 as a guide on this as I do not have any experience overclocking GPUs.

Most of the guys on this thread were able to get 1200Mhz core clock and 5800Mhz memory clock on around 1095mV. Now I do understand that all GPUs are slightly different and will have different OCing potential, more on that later.

So to begin I tried upping the core clock to 1050Mhz without touching the voltage or memory clock. This worked fine so I just decided to test 1200Mhz core and 5800Mhz memory and go from there. This was an instant BSOD on the Unigine Heaven benchmark. Okay, so to make a long story short it was eventually stable, though I had to lower the memory clock 400Mhz. BUT, it needed 1190mV to do this, even with the memory reduced 400Mhz! Now back to GPUs being different. A few of the guys in the thread had the reference card design, with only one fan, somewhat limiting their ability, yet they still managed the OC at around 1095mV. Thats nearly 0.1V more! The real kicker is I got the OC Edition graphics card, which is supposed to be the best of the 7850s for the best OCing potential.

Am I doing something wrong or did I just end up with a bad card?

System:

Asrock z77 Extreme4
i5 3570k @4.2Ghz
Sapphire HD7850 OC Edition (2GB DDR5 Memory)

Thanks for anyone who managed to read all that. Please post any advice, no matter how obvious it may seem, I'm new to this 😀

Once again, Thanks!

 

[stickmansam]

Sometimes it is a bad card
Memory overclock is a bit variable esp sicne different vendors use different ram chips
The GPU core clock is variable

What is your GPUZ ASIC value?

 

[Biggles_]

Sometimes it is a bad card
Memory overclock is a bit variable esp sicne different vendors use different ram chips
The GPU core clock is variable

What is your GPUZ ASIC value?

I have been using Asus GPU Tweak.

Just downloaded GPU-Z, got 86.6%, though I have heard that they are not accurate.

Any more help would be appreciated!

 

[rdc85]

Factory Overclocked card doesn't means it better card... (partially)

IMO, it's for people who doesn't had confidence for O.C. by them self...

by lowering memory speed doesn't means it will help the GPU core speed O.C. it just make sure no/less instability caused by the memory..

because of this, some people find the stable overclocked core speed before try overclocking the memory...

not familiar with GPU O.C. but i think this how u need to do it...

find the highest stable clock in default volt...
after that increase the volt a little and find the highest clock for the voltage..
repeat until it hit the temp/voltage limit and reduce the clock a little...

for me, I don't like tempering with voltage....

 

[cats_Paw]

Normally, as far as i know, the core is what needs more Volatage to be overclocked, while the memory requires little.

Each card is diffrent not only means that the ammount of OC you can get is diffrent, but also means that the settings it needs to not BSOD are diffrent.
THis means that in some cases , while a guy has a good Overclock at 1200/5800/1095, your settings may be totally diffrent (dosent mean worse, just diffrent).

This is why you always overclock by a small gain and test again, and NEVER do a a just like that to higher clocks. It can potencially damage your GPU.

If you dont do it patiently, you will pay the price for it.

 

[rdc85]

.....This is why you always overclock by a small gain and test again, and NEVER do a a just like that to higher clocks. It can potencially damage your GPU.....

+1

 

[Biggles_]

Normally, as far as i know, the core is what needs more Volatage to be overclocked, while the memory requires little.

Each card is diffrent not only means that the ammount of OC you can get is diffrent, but also means that the settings it needs to not BSOD are diffrent.
THis means that in some cases , while a guy has a good Overclock at 1200/5800/1095, your settings may be totally diffrent (dosent mean worse, just diffrent).

This is why you always overclock by a small gain and test again, and NEVER do a a just like that to higher clocks. It can potencially damage your GPU.

If you dont do it patiently, you will pay the price for it.

Okay thanks for this. Is it a good idea to start on stock volts and see how high I can raise the core clock before it crashes? One question, which do i raise first, or do I raise them at the same time?

 

[smeezekitty]

A: It is not a "terrible" GPU even if it does not overclock well. A 7850 should do find on most things without overclocking.

B: You should always start out with a small overclock and work from there. Do not instantly apply a high OC.

 

[Biggles_]

Okay, so what I am doing at the moment is this: I am at stock voltage and memory clock and upping the core clock by 10Mhz at a time and running the Unigine Heaven benchmark to test stability.

When I reach the max stable core clock on stock voltage, do I up the memory clock or just leave it?

Thanks!

 

[wanderer11]

Yes when you find the max core then you can start tinkering with memory. I like to keep a log of OC values and benchmark performance just to see how much it really helps.

 

[Biggles_]

Yes when you find the max core then you can start tinkering with memory. I like to keep a log of OC values and benchmark performance just to see how much it really helps.

I managed to get up to 1070Mhz stable on stock voltages from 920Mhz. When I got to 1070Mhz I also upped the memory 200Mhz from 5000 to 5200Mhz. I did some Heaven benchmarks and got about 6 frames higher than stock, but only increased around 4 frames in Far Cry 3 on max settings. Is this normal? Also, should I start upping the voltage for more core clock speed or leave it where it is?

Thanks Heaps!

EDIT: I like to keep a folder full of previous benchmarks too! It sure does speed it up when benchmarks take over 5 minutes!

 

[wanderer11]

That really does seem normal. For comparison, my 7870 from 1000/1200 to 1200/1250 only nets me ~5 more fps in just cause 2 (one of the few game benchmarks I have). If you think it is worth it then go ahead and slowly increase voltage. That is where you can damage your card so be careful.

 

[rdc85]

yup so far so good,

when increasing the volt increase just a little (and always remember the safe limit of the card), and re-testing to find the new stable clock....

Also there an important thing, when u get the max speed and max voltage and else seems stable...

it's recommended to step down the speed a little.. it will helps for prolong the lifetime of the card... (since it will wears out over time)

 

[Biggles_]

yup so far so good,

when increasing the volt increase just a little (and always remember the safe limit of the card), and re-testing to find the new stable clock....

Also there an important thing, when u get the max speed and max voltage and else seems stable...

it's recommended to step down the speed a little.. it will helps for prolong the lifetime of the card... (since it will wears out over time)

Well I have increased the core clock to 1080 and it was stable, but I dialed it down to 1070 just to be sure. I came from 920Mhz and only saw about 5 frames difference, so I don't thinks its worth adding voltage to get another 100Mhz and risk damaging my card.

Thanks for everyone's help, any more tips would be appreciated!

 

[Biggles_]

Best answer selected by Biggles_.