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ATI 4850 Overclock Results

ViciousXUSMC

New Member
Joined
Jul 4, 2008
Messages
117 (0.02/day)
System Name Vicious's Rig
Processor Q6600 @ 3.6ghz @ 1.4v (Windows)
Motherboard Asus P5Q Deluxe
Cooling Thermalright Ultra 120 Extrme with S-Scyth fan
Memory 2x2gb Mushkin DDR2 800
Video Card(s) 2x Visiontek 4850 @ 675/1000
Storage 2x 640gb Western Digital
Display(s) 37" Westinghouse LVM37-W3
Case Antec P182 Special Edition
Audio Device(s) X-Fi Xtreme Music
Power Supply PC Power & Cooling 750w Silencer
Software Windows Vista x64 Ultimate
Benchmark Scores 3dmark06 18,582
I know we have a buss load of overclock results postings within the forums probably, but they are all scattered all over the place and tied in with other threads. I would like to have one thread very specific to the 4850's and your max stable overclock so that we can use it as a basis on what to expect on the cards.

Please post

Brand
max stable clocks and how determined
if its stock or volt moded (and hard mod or bios mod)

Me personally I have 2 Visiontek 4850's in crossfirex
so far my max stable seems to be 675/1000 with stock bios/voltage it has only been determined by playing games so far, I have had no issues or crashes with maxed out CoD4, Crysis, and other games.

Temps are great, high 50's low 60's idle with a 50% fan speed locked via edited CCP profile and in the 70's load.

Also wonder if anybody has tested what gives a larger benefit and can share, overclocking the core or the memory? In the past with my nvidia cards I always experienced a "push pull" relationship between the core and memory. If I maxed out the core to its highest stable point the memory would not overclock nearly as high as if I lowered the core down and raised the memory instead. So rather than finding the max for both, I had to find the best balance, in the case of my old 7800GTX I found that the memory held more importance than the core.

Soon here I may flash my bios to 1.2v and re-do the fan speeds and see what I can get. Waiting on others to report back on temps and stability before I make my move.
 
I have a single Visiontek 4850 flashed to Asus for fan adjustment. With stock fan at 55%, OC was 690/1130 (got lucky and got good memory I guess). Now I have modded BIOS to 1.2v for 3D and have it 700 core for now, will flash higher later, hoping for 725 stable without having to set fan much above 60%. Although I DO have a side 120mm fan on my Antec 900 manually adjusted up higher blowing right onto it too. For $179 I am REALLY happy with my results!
 
Mine are kinda toasty I got to 86c almost 90c with the fan at 60% but thats running a 100% load with ATI tools artifact tester, and 2 cards in crossfire. Its a P182 case and it only has one intake, for that part of the case and its got a dust cover on it and everything. I may have to look into extra fans, but the 2nd card is right ontop of wires so its not going to get much air no matter what I do.

Did you see any big change in temps with the 1.2v change? I want to do that so I can go for maybe 710mhz core but I have to go thru alot of trouble flashing the cards 1 by 1...

I just removed 2 of the cd bay covers and there is enough negative pressure in there to suck a piece of paper to the case, so I just increased the airflow a good amount, but it makes the system louder and that air is only really going to reach the cpu cooler not the video cards on the bottom part of the case.
 
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I haven't had a chance to see how my temps are affected yet. I will play some GRID tonight and get it nice and warmed up and see where I stand. For you it sounds like the extra airflow may help. Even though you say it goes to the CPU area, it will still help the airflow for the whole case.
 
Personally, I see no reason to go beyond 730-740MHz core....I had a very small increase in performance going from that to 770MHz core. I had a real good boost going from 700 to 725MHz thou:).

I'm using a VisionTek with MSI bios, it's pencil modded(1.3v) for my bench setting, and has a simple VF900:)....Enjoy:

Screen020.jpg


I'll go farther soon, I've been flashing my bios, now it's too easy with software:D....expect 800 tonight;)
 
Gigabyte HD 4850 with MSI bios

Max core clock - 830mhz - stable with everything - 1329mV
Max mem clock - 1075mhz - stock volts

With an accelero s1 fitted with a 120mm and 80mm fan, core temp never goes above 55C with atitool artifact scanner with ambient temps 25C. With furmark it can hit 60C.

ev7.png


Cant be bothered to take the card out to go further.
 

Attachments

Gigabyte HD 4850 with MSI bios

Max core clock - 830mhz - stable with everything - 1329mV
Max mem clock - 1075mhz - stock volts

With an accelero s1 fitted with a 120mm and 80mm fan, core temp never goes above 55C with atitool artifact scanner with ambient temps 25C. With furmark it can hit 60C.

ev7.png


Cant be bothered to take the card out to go further.

Can I see your temp page in GPU-Z?....My temp #2 is hitting like 80+....soon as it hit's 90, it artifacts, just wana see what your temp 2 is. It's weird cause my other temps are in the 60's, and it climbs to the 80's+:wtf:
 
My temp2 can get into the 90's too. Its my case the p182 is designed to be super quiet and has those dust filters and things on it.

I hit 90c core and 92ish for temp#2 with the artifact tester on my top card, soon as I opend the front case door, then took off the dust filter and opened the door for that my idle went from 55c to 50c and max load from 90c to 80c.

However I wont leave the computer in that conditon it will get dusty inside fast and it goes from near silent to pretty loud. Fans at 60%

I will flash the bios uventully for fan speed if anything because having it locked at 60% is surly going to shorten the life of the fans vs having them scale with temps. Also going to do the 1.2v for the core and shoot for 715mhz.
 
I'm running 100% stock on a Visiontek 4850 with the following OC.

GPU: 690MHz
Memory: 1133Mhz

Everything runs fine too. COD4. TF2 and Bioshock. But honestly I havent noticed any performance increase. You guys think these OC are any good?
 
I'm running 100% stock on a Visiontek 4850 with the following OC.

GPU: 690MHz
Memory: 1133Mhz

Everything runs fine too. COD4. TF2 and Bioshock. But honestly I havent noticed any performance increase. You guys think these OC are any good?

That's exactly what my same card does unmodified other than the fact I ran 675 to be completely stable before I upped my fan speed. It looks like our Visiontek cards have pretty decent memory on them!
 
Stock DIAMOND HD 4850

gpuzsu5.gif


The Auto-Tune option in the CCC went up to 690/1138, but I backed them down to 680/1125 (9%/13% overclock). I'm pretty sure it can go a little higher if I tell the fan to go faster or something, but I'm thinking of returning it and getting the HD 4870.
 
Can I see your temp page in GPU-Z?....My temp #2 is hitting like 80+....soon as it hit's 90, it artifacts, just wana see what your temp 2 is. It's weird cause my other temps are in the 60's, and it climbs to the 80's+:wtf:

Thats the VRMs temp. You need active cooling for that if you want to put 1.3v+ through them. You need to point a fan at them. The vf900 doesnt do that and thats the problem you have. Because Im using an S1, the 80mm fan I am using is directly above the VRMs. I havent put any ram sinks on, but I bet if you did, the air from the main vf900 fan moving over the sinks would be good enough.

4w8.png


edit: I have to correct this post. None of the temps represent the VRM temperature. The latest gpu-z reflects that.
 
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Here are mine if anyone wants to know.

dk8.png
 
Thats the VRMs temp. You need active cooling for that if you want to put 1.3v+ through them. You need to point a fan at them. The vf900 doesnt do that and thats the problem you have. Because Im using an S1, the 80mm fan I am using is directly above the VRMs. I havent put any ram sinks on, but I bet if you did, the air from the main vf900 fan moving over the sinks would be good enough.

Yea, I have no ram-sinks on my ram, they work fine:p....Getting some soon thou. I used the Zalman sinks for the VRM's...and I have a 60CFM 12CM fan pointed directly at them, they stay at 77 at 1.21v:).

BTW, I love my card:p....745MHz on stock voltage:D, maybe I'll get my pencil and MM out soon:pimp:
 
Shot001.jpg


That's my load temps with the VF900, in a very hot room:(. My MM reads the voltage at 1.21v, set to 1.2 in bios.
 
Hmm alot of 680-690 stable, mine crashed out of crysis & cod4 with 690, but that was before I raised the fan speed, so it may be temp related.

Suppose if I am already getting 60fps I dont need to push it harder as I would rather have a quiet system than worry about opening up my case and removing the dust filters for cooling every time I want to play a game.
 
7uq.png


These are the temps I get with my 4850/Accelero S1 at 700/1100 settings, obviously now it's idling in this screenshot. This is at default voltage.

I was thinking of BIOS flashing to 1.2v, or using Eastcoasthandle's CCC profile mod to the same voltage.

Because the chip/vrms seem cool in this screenshot, what chance at 750Mhz? Right now, the chip loads at about 43c.

Would be grateful for any input.

:)

Edit: Here are the 3d clocks:

2c6.png
 
Im at 720/1050 now with a bios mod for 1.2v for the gpu core. Not sure its 100% stable but should be, I got a driver fail in UT3 after about an hour but it recovered. 710 was stable for sure with over 30 min on artifact tester but it only runs 1 of my 2 cards....
 
so Im taking it these are very easy to voltmod and bios mod no problem? I see folks using an MSI bios on a Gigabyte.Asus card and what not.
 
Well there are some pretty easy looking pencil mods, a bios mod is nothing more than saving your bios or downloading it from the database here, opening it up typing a few keys in the right areas to edit it and then flashing it back.

It was not the overclock that really motivated me to do a bios flash, it was the fan speed issue. RBE lets you set the fans to run at a % based on temps and now its great, silent but cool at idle (about 30% at 60c) and then faster and audible during gaming but I cant actually hear it over the game (60% around 85c)
 
when I get my new motherboard I'll stick my Thermalright V2 +14 ram sinks +90mm +80mm fans on it
and oc it.
 
I can seem to get 730/1050 to work consistently (at least in 3Dmark06). Any higher core, and it blows up 3Dmark with a vertex buffer error from DX9. If I raise the core or the memory, it blows up each time.

I haven't done the pencil mod yet, so I guess I'm just voltage constrained at this point, even though I've set voltages to 1.4 in the 3D sections of the BIOS. I guess most guys that measured see only 1.25 with that setting, which seems to be the highest you can get with the BIOS.

Wheres my pencil, gotta be somewhere around here
 
I have a powercolor and visiontek, in a p35 board in cf they both do 740/1100. in an x38 board in cf they both do 725/1100 (and still score exactly 1k points higher in 3dmark06 then the p35 setup).

Both still running the stock heatsink, bios modded to 1.21v and fan ramp up changed to start ramp at 20c and hit 100% fan speed at 60c (stock bios doesn't seem to start ramp until the card hits 41c?!?!?! and doesn't hit 100% fan speed until about 85c).
 
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