4890 OC Help

[Sonikku13]

I am a new person to talk around here. I need some questions answered, as I am new to overclocking. I would prefer straight-forward answers, but long answers are fine as long as they are readable.

I had been running on integrated graphics since 1998, with three computer changes. In early 2007, I realized that they would not play games very well. I kept holding on until I succumbed on June 12, 2009, when I built my first computer. Since then, my Radeon HD 4890 wants me to overclock it to 1 GHz.

There are no screenshots to give, as I have not torture tested my GPU for enough time. However, I can say that for as long as I run GPU-tool, my Radeon HD 4890 seems to run fine at 1 GHz on core and 1140 MHz on memory at 1.425V. Since I don't really care about noise, I was running the stock cooler at 100% to keep VRM temps low, but they were encroaching 90 degrees Celsius. Memory and core temps were fine, both under 70 degrees Celsius.

When I use ATI Overdrive, it gives me 1 GHz core at 1.35V.

I play games such as Empire: Total War and Sins of a Solar Empire. I plan on getting Modern Warfare 2 at launch. I play at a 1280x1024 resolution, so I know my GPU is overkill.

Simple things like a game crashing will mean I know it is unstable, but I have not tested it yet.

So this is where my questions come in. They may be simple, but it's to be cautious and to help my confidence.

1. What is the maximum safe voltage for the Radeon HD 4890 on the stock cooler?
2. What is the maximum safe temperatures of the VRMs of the Radeon HD 4890 on the stock cooler?
3. Should I try playing games at these overclocked settings to test stability?
4. What voltage should I try first, 1.35V or 1.425V.

 

[Eureka]

1. There's no 'safe' voltage, all overvolting has its risks.
2. 90C is generally an ok limit for heat.
3. Use GPU tool to test for artifacts, Crysis for real application
4. 1.35 first, then bump it up until GPU tool gives you no artifacts.

 

[MrK6]

Originally posted by: Sonikku131. What is the maximum safe voltage for the Radeon HD 4890 on the stock cooler?
2. What is the maximum safe temperatures of the VRMs of the Radeon HD 4890 on the stock cooler?
3. Should I try playing games at these overclocked settings to test stability?
4. What voltage should I try first, 1.35V or 1.425V.

1) For a new overclocker, the max I'd go is 1.4V, that should be OK for everyday usage until you figure out the nuances of your card. Also make sure you keep an eye on your temps, not just your GPU, but everything else on the card (especially the VRMs) - use GPU-Z http://www.techpowerup.com/downloads/SysInfo/GPU-Z/

2) It's more relative - the higher the temps go, the more unstable the card gets and you'll also lower the lifetime on the part. I'd try to stay below 90C as a general rule.

3) Definitely, that's one of the best ways to test it. If you have any, test some really demanding games (i.e. newer titles) to check for stability (play for a couple of hours in a row). I use the Crysis series and Left 4 Dead with good results. I also use Furmark - http://www.ozone3d.net/benchmarks/fur/ which really heats up the card and is a great stress test when overclocking on the fly.

4) Whatever you want. Decide how far you want to overclock and how much heat you want your card to put out, then go from there. I'd try it at stock voltage first and see how far that gets you, then go from there.

Best of luck :thumbsup:

 

[Sonikku13]

Going to test at 1000 MHz core/1100 MHz memory at 1.4125V now. Started at 1:08 PM and first error at 1:17 PM.

Same OC at 1.425V. Started 1:40 PM, backed off at 1:44 PM due to 90 degree Celsius VRM temps.

I might have to try something different. Maybe start off at 1.35 and test.

 

[MrK6]

Sounds good; set a voltage and adjust the clocks for stability, not the other way around :thumbsup:

 

[error8]

Be careful with Furmark and 1.41 V of the card. It can heat up the VRMs like crazy!
In my opinion the stock heatsink will have issues in keeping the card cool even at 1.35 V, in Furmark.

 

[Sonikku13]

I'm fairly sure it can run at 1 GHz/1125 MHz at 1.425V. Now knowing that my Radeon HD 4890 can run at 1 GHz, I'm happy. However, I'm not going to leave it like that in the scenario that I forget something or do something wrong and it blows up. No one wants a dead card thats their own fault or someone elses, as far as I've seen. I'm going to do more testing for an OC at stock voltage.

I'll end up updating it later when I get done testing it.

Late update - It seems to be stable at 910 MHz/1050 MHz at stock voltage. ATI Overdrive has lower tolerance for high memory clocks, it seems.

 

[Eureka]

Yeah, the card really needs the voltage for speed. I keep mine at 975/1150 with 1.35v.