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How to overclock a 7850 past 1050MHz?

eyesonly said:
Just bought a Asus 7850 directcu2 (dc2-2gd5).

I've installed asus gpu tweak (latest version) and noticed that the default voltage is quite high, namely 1.21 volts.
I've read here that this is the case for some cards, but is there any way to get it any lower?

Asic quality is 68,7:(
Click to expand...

if your asic's 68.7% id seriously consider dsr/refund asap and order another card
 
ASIC quality is VERY IMPORTANT for these cards. I have now installed 4 7850's and ASIC quality directly impacts on overclockability. My original card has 84% and easily clocked past 1250MHz (1400MHz was even benchable @ 1.3v with third party air cooling). Two cards were in the mid 70's and could not reach 1200MHz, even with max volts and 100% fan. My latest card was 69% and sucked big time. It can just about do 1100MHz on max volts.

ASIC also affects default volts and temperatures.
>80% ASIC = 1.05v to 1.075v
72-79% ASIC = ~1.138V
<71% = ~1.21V

High ASIC's do not guarantee great overclocks, but they GRATLY improve the chances. Low ASIC's have the opposite affect.
 
Am hoping that someone may be able to help me out with a small problem that Im currently experiencing.

Ive just put together a new build this week, spec below:

Motherboard: Gigabyte z77x-ud5h
CPU: i5 2500k
CPU Cooler: Antec Kuhler H2O 920
Ram: Kingston HyperX 8Gb 2133Mhz DDR3 (2x4Gb)
Graphics: Sapphire Radeon HD 7850 OC 2Gb GDDR5
HDD: 2x Seagate Barracuda 1Tb SATA 6Gb/s (ST1000DM003)
Optical drive: LG BH10LS38 Super Multi Blue
PSU: Coolermaster Silent Pro M2 850w
Case: Antec Three Hundred Two
Case fans: 4x Antec True Quiet 120mm (low speed - [email protected], high speed - [email protected])
OS: Windows 7 64bit

Im running the following m'board BIOS - F11, and the CPU is overclocked to 4.5Ghz as follows :

CPU Vcore - 1.335v
VTT - 1.060v
PLL - 1.810v
BCLK - 100.1
Vcore load line calibration - Extreme


Im running Catalyst v12.6 (I have activated AMD Overdrive via the Catalyst drivers) and using Asus GPU Tweak v2.1.7.1 (I have ticked GPU voltage and Overclocking range enhancement) and trying to benchmark the GPU using Heaven 3.0.

The base clocks for the GPU are:
GPU Clock - 920Mhz
GPU Voltage - 1138mV
Memory Clock - 5000Mhz
Fan speed - Auto

Now the problem Im having is that when ever I try to overclock the GPU, Heaven either refuses to get past the loading screen once you hit play or it starts the benchmark and after a couple of seconds Heaven locks up.

I will admit that Ive not tried any gradual setting changes, and jumped straight into the following:

GPU Clock - 1200Mhz
GPU Voltage - 1138mV
Memory Clock - 5800Mhz

I have no idea what Im doing or not doing wrong, and would appreciate any advice/ help as I would love to OC this card as I know that there are potential some huge gains to have from it.
 
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I have just read back through this thred and noticed that 555BUK mention that the ASIC Quality can effect the OC potential of the card. So Ive checked mine and its at 73.6%, which may explain why it wont OC so well :(

Going to run some more tests, and post again shortly.
 
dhill said:
Am hoping that someone may be able to help me out with a small problem that Im currently experiencing.

Ive just put together a new build this week, spec below:

Motherboard: Gigabyte GA-Z68X-UD3H-B3
CPU: i5 2500k
CPU Cooler: Antec Kuhler H2O 920
Ram: Kingston HyperX 8Gb 2133Mhz DDR3 (2x4Gb)
Graphics: Sapphire Radeon HD 7850 OC 2Gb GDDR5
HDD: 2x Seagate Barracuda 1Tb SATA 6Gb/s (ST1000DM003)
Optical drive: LG BH10LS38 Super Multi Blue
PSU: Coolermaster Silent Pro M2 850w
Case: Antec Three Hundred Two
Case fans: 4x Antec True Quiet 120mm (low speed - [email protected], high speed - [email protected])
OS: Windows 7 64bit

Im running the following m'board BIOS - F11, and the CPU is overclocked to 4.5Ghz as follows :

CPU Vcore - 1.335v
VTT - 1.060v
PLL - 1.810v
BCLK - 100.1
Vcore load line calibration - Extreme


Im running Catalyst v12.6 (I have activated AMD Overdrive via the Catalyst drivers) and using Asus GPU Tweak v2.1.7.1 (I have ticked GPU voltage and Overclocking range enhancement) and trying to benchmark the GPU using Heaven 3.0.

The base clocks for the GPU are:
GPU Clock - 920Mhz
GPU Voltage - 1138mV
Memory Clock - 5000Mhz
Fan speed - Auto

Now the problem Im having is that when ever I try to overclock the GPU, Heaven either refuses to get past the loading screen once you hit play or it starts the benchmark and after a couple of seconds Heaven locks up.

I will admit that Ive not tried any gradual setting changes, and jumped straight into the following:

GPU Clock - 1200Mhz
GPU Voltage - 1138mV
Memory Clock - 5800Mhz

I have no idea what Im doing or not doing wrong, and would appreciate any advice/ help as I would love to OC this card as I know that there are potential some huge gains to have from it.
Click to expand...

You need to raise your GPU voltage. Suggest you read this thread from the start, plenty of OCing advice in here. Do it properly, i.e. raise core speed slowly until it gets unstable then give it a small voltage increase of 25mv or so until it's stable again. Rinse, repeat.
 
AlfBaxter said:
You need to raise your GPU voltage. Suggest you read this thread from the start, plenty of OCing advice in here. Do it properly, i.e. raise core speed slowly until it gets unstable then give it a small voltage increase of 25mv or so until it's stable again. Rinse, repeat.
Click to expand...

This, 1138V at 1200 gpu clock is highly ambitious.

I will admit that Ive not tried any gradual setting changes, and jumped straight into the following:
Click to expand...

ASIC is not an indication of how good or bad an overclock will be. I have a GPU with an ASIC quality of 75% and it reaches 1200 clock all day long. Just do it right instead of winging it otherwise you're bound to run into problems.

Also as mentioned in the thread a million times, if you don't take iterative steps with the overclock you'll never know when memory correction kicks in and the point where the card starts to throttle itself with a certain clock speed.
 
Cheers for the heads up guys, am gonna run through OC'ing the card again the proper way, might take me a while but as you rightly say will give me a better idea of where the cards breaking point(s) is/are.

Will report back in while :)
 
wazza300 said:
thank god for ssd's,sure come in handy when it flashes a multicoloured screen due to a failed gpu oc attempt
Click to expand...

I do know that feeling buddy! Shame I dont have a ssd though, good job its a fresh install of Windows 7 though lol

Getting there slowly with the OC'ing now, is it the GPU clock that pushes the need for the extra volts and not the memory clock?

Also whats classed as a safe voltage to push these cards to? Mine is limited to 1225mV in the Asus GPU Tweak software, is that classed as safe?
 
Ok update time....

After some in-depth and time consuming testing it seems that my card doesn't like going above a GPU Clock speed of 1170Mhz with a Memory Clock of 5800Mhz @ 1220mV, but the good news is that it seems nice and stable.

A Heaven score of 1526 doesn't seem to be to bad either. Full results can be found in the Official Unigine Heaven DX11 3.0 Benchmark Scores thread here: http://forums.overclockers.co.uk/showthread.php?t=18386056&page=32

CPU: i5 2500k @ 4.5Ghz
GPU: Sapphire 7850 OC 2Gb GDDR5
GPU Clock: 1170Mhz
GPU Voltage: 1220mV
Memory Clock: 5800Mhz
Overclocking software: Asus GPU Tweak v2.1.7.1
Video Driver: Catalyst v12.6
Heaven Score 3.0: 1526
 
Been looping heaven benchmark this afternoon, and I thaught 3dmark was going abit too easy on my card ;). Had to drop the clocks from 1210 to 1180 to stop heaven causing the driver to stop responding. So 1180/1500(6000) seems to be ok for heaven looping although the odd white screen flicker did creep in, due to memory?

bfs0k.png


Adjusting Powertune slider didnt seem to help or hinder. At 1190 core, the first run might make it through, but the second wouldnt.

I cant seem to make any voltage adjustment options appear in Asus tweak tool, just the Extended overclocking option so im at a wall now I think for this card (Powercolor PCS+ HD7850) Default Voltage is 1219mV full load. 825mV idle.
 
Last edited:
IRLeetly said:
I've been very tempted to buy also, need an upgrade but may wait until September as I fear they will get cheaper when Nvidia bring out their alternative.
Click to expand...

By then everything will be a cheaper such as life with PC components.

I got a small amount of artifacting with the following

GPU Clock: 1100Mhz
GPU Voltage: 1210mV
Mem: 4800

Should I dare pushing it anymore? Brand new MSI R7850.
 
Pazz said:
By then everything will be a cheaper such as life with PC components.

I got a small amount of artifacting with the following

GPU Clock: 1100Mhz
GPU Voltage: 1210mV
Mem: 4800

Should I dare pushing it anymore? Brand new MSI R7850.
Click to expand...
I wouldn't, you've already reached an unstable point. I'd back down a bit. Also, is it me or does anyone else find Sapphire's TriXx overclocking utility to be a bit buggy? Like when I click on it while it's in in the task bar, sometimes it doesn't even load up and when it does, some of the UI partially loads and stutturs and no longer applies the overclock until I restart my PC.
 
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