Easy BIOS volt mod for 7800GT

[Guest Milkshake]

Well from what Ive gatherd from my own thoughts, correct me if I'm wrong but Im pretty sure the delta is the booster for when you play in 3d performance mode, it adds the extra mhz. Its good so that you can be using windows and it wont boost up your oc that high. Hmmm maybe more tests are needed, because I've read about the delta helping and ive read about the delta making no change. The only thing I see it as good for is not running your gfx card on a high oc all the time, only while using intense 3d stuff.

[Redbeaver]

but still, if that is the idea, why didnt it boost the core as many as the delta when i bench 3dmark? i scored lower with the delta...

[Raphie]

As i understood the DELTA is used to lock the offset already on bios level (what you normally would do with coolbits) so if your happy with certain coolbits settings, you can put the delta value (OC clock - Stndrd clock) in the BIOS

[Guest Milkshake]

Um, I dont think thats it. I have done some reasearch and after many sources which say the same thing...The delta is used to run other parts of the card like shaders and stuff, Because they run at different speeds:

 

“What is this ‘clock delta’?”

 

We’ll use the example of a Geforce 7800gt, as that is what I use. A 7800GT has specs of 400mhz core and 1000mhz memory. However, unknown to many, the 7800 series actually run certain parts of the core faster than others. The Core clock still runs at 400mhz, however, there is a delta so that another two parts of the card (Shaders and ROPS) run at a certain amount faster. This certain amount is the delta. At stock, the delta on a 7800gt is 40mhz. In other words, the shaders and the ROPS work 40mhz faster than the rest of the card. By altering the clock delta, from within the BIOS, it is possible to alter how much faster these other parts run at.

 

“Why Would I want to do this?”

 

For a 7800gtx, there is in truth, very little point in doing this. However, this doesn’t apply for the 7800gt series. Legend has it that the pipeline yields on the G70 (or nv47 as some believe it to be) have been extremely good – 24 pipe cards are bountiful. Therefore, in order to create the 7800gt series, they have simply taken the very poor clocking G70’s, and disabled (laser cut?) 4 of the pipelines.

This has led to myself and many others to be extremely disappointed with the overclocking ability of the 7800gt. However, one way of getting the clock a little bit higher (and scoring an extra 200+ points in benchmarks) is to remove the clock delta. This will make it possible to clock the core of the card slightly higher, while maintaining the clocks on the other two parts.

As an example;

Before the edit, I was able to reach 470mhz on the core, (512mhz including the delta) and my 3dmark03 score was 17689. After altering the BIOS, and getting rid of the delta, I was able to clock to 495mhz on the core. This meant that all parts were clocked at 495 mhz, and thus, while some parts were slightly lower, other parts were significantly higher, and this led to a score of 18k. In other words, it can be hugely beneficial.

 

 

Here is my references:

 

Delta Explanation:

http://www.mvktech.net/component/option,co...id,13/id,25520/

 

I suggest you check this guide out:

 

7800gt TIMINGS:

http://www.mvktech.net/component/option,co...id,28109/#28109

[Guest Milkshake]

I have a question...

 

If you want to up the voltage to 1.55, do you set the last one in the voltage table #3 to 1.55 and leave the rest @ 1.2 1.3 1.4 ? or do you up them all 1.25 1.35 1.45 1.55 ?

[Amps]

Some 7800Gt cards do not use Delta and example of one that doesn’t is the BFG 7800GT. They did on there first rev cards but not on there later ones. There are a few other manufacturers that don’t.

 

Has anyone successfully flashed a bfg card ?

[TroOper]

yes,

i have a BFG 7800 OC

max i got with the bios mod was 535 on the core, including a 40 delta

i am currently running it default BFG speeds with a 40 delta it scores 7680 in 3dmark 05

[Redbeaver]

I have a question...

 

If you want to up the voltage to 1.55, do you set the last one in the voltage table #3 to 1.55 and leave the rest @ 1.2 1.3 1.4 ? or do you up them all 1.25 1.35 1.45 1.55 ?

 

i didnt. but its too hot for me so i drop back down to 1.50. but it did gives even higher overclock. a little bit.

[noahsark1126]

Mine is volt modded. Before at 1.4V coolbits picked 496/1.13, now it picks 513/1.17. That increased my 3dmark05 score by about 400. I also had absolutely no problems with it, very easy. My load temps went up about 5 degrees (from ~58 to ~63). I've never seen it hit above 65, and it rarely reaches that (I'm on air, not stock, but still air). Also, if you think about it, this is only a 7% increase in voltage which should be fine. For CPUs and GPUs, under 10% is fine, 10-15 is pretty safe, 15-20 is somewhat safe, and 20+ is probably gonna fry it. So, this is actually less than 10%, so it should be perfectly fine.

[silenze]

I've done my BFG card.. max stable core through aquamark3 before was 522Mhz, after is 552Mhz, 510-->540 in 3Dmark's.. measured with DMM. All my best results are at the bottom of my signature...

[Redbeaver]

I've done my BFG card.. max stable core through aquamark3 before was 522Mhz, after is 552Mhz, 510-->540 in 3Dmark's.. measured with DMM. All my best results are at the bottom of my signature...

 

what kind of cooler u use, Silneze? that MWZ thing on ur sig....? is that water?

 

wow good job on the high core! i maxed 515 before artifact starts to show... but managed to get the mem at 1.23

[Redbeaver]

Mine is volt modded. Before at 1.4V coolbits picked 496/1.13, now it picks 513/1.17. That increased my 3dmark05 score by about 400. I also had absolutely no problems with it, very easy. My load temps went up about 5 degrees (from ~58 to ~63). I've never seen it hit above 65, and it rarely reaches that (I'm on air, not stock, but still air). Also, if you think about it, this is only a 7% increase in voltage which should be fine. For CPUs and GPUs, under 10% is fine, 10-15 is pretty safe, 15-20 is somewhat safe, and 20+ is probably gonna fry it. So, this is actually less than 10%, so it should be perfectly fine.

 

so that means if i crank it up to 1.6, its still pretty safe?