Article: 7800GT OCing peculiarities and unlocking

[Cooper]

As it was reported earlier the G70 core has two frequencies - the ROPs frequency is higher than core`s for 30 MHz. But how will it scale during OCing ? Guys from Hardware.fr have made some investigation. And this is what they got :



The first column shows the core speed as you can see it in any hardware utility like RivaTuner. the second is the Pixel pipelines frequency. And the third - vertex processor units frequency. As you see the numbers differs. This leads to some sort of usefull OCing steps which can be ilustrated by this graph (for GTX version)



Unlocking the missing quad of pipelines is another story. Overclockers.ru reports that HKEPC (and IMO other lucky guys) could unlock their`s GTs cos it was engeneering samples, which won`t come to market. So only the actual owners of 7800GT will proove (or dispel) this.

[DriveEuro]

The two frequencies part doesn't seem much different than the 7800GTX.

If they cards DO unlock, then they'll be the where everyone goes.

[Cooper]

Originally Posted by DriveEuro

The two frequencies part doesn't seem much different than the 7800GTX.

It`s common for all G70 cards

[don_vercetti]

what's an average overclock on air then?

I'll be getting one of these cards, just waiting for a slight price drop.

[Cybercat]

Really is fairly confusing. Can't wait til the new version of RivaTuner comes out with support for the additional clocks.

[bigZ]

There are actually more than two clocks inside G70 - there are many clocks and at least three clock derivatives, and you will not be able to unlock these cards AFAIK.

G70 is much the same as NV43 A4 revision and NV41 silicon - there's some sort of protection (either in the drivers, or in the silicon) that cannot be bypassed by NVStrap or a BIOS modification.

[Ackbar]

Originally Posted by bigZ

There are actually more than two clocks inside G70 - there are many clocks and at least three clock derivatives, and you will not be able to unlock these cards AFAIK.

G70 is much the same as NV43 A4 revision and NV41 silicon - there's some sort of protection (either in the drivers, or in the silicon) that cannot be bypassed by NVStrap or a BIOS modification.

Interesting... has anyone looked into it specifically to figure out what the actual cause of the protection might be?

The pipes don't seem to matter very much, just the clocks. There are some articles with engineering sample cards that were unlocked and producing similar numbers. Only clocking to GTX speeds seems to have a dramatic effect.

[koei]

Tried unlocking with the current RivaTuner, altough it said 24x1,8x1 under the NVStrap, it seems like it didn't apply it. Maybe later version will be able to do it.

[don_vercetti]

unwinder (the rivatuner maker) said that it doesn't apear unlockable, as yet.

[Ackbar]

Originally Posted by koei

Tried unlocking with the current RivaTuner, altough it said 24x1,8x1 under the NVStrap, it seems like it didn't apply it. Maybe later version will be able to do it.

What do you mean it seems like it didn't apply? I didn't think that anyone else could even get it to work under the NVStrap.

[koei]

I mean I installed NVStrap, goto the pixel/vertex units configuration and select custom, then change the disabled units to enable. After that's done, it showed under NVStrap that I selected the 24x1 and 8x1 configuration, but after reboot, it still shows 20x1 7x1 under main menu of RivaTuner and benchmark shows the same performance results.

[Ackbar]

Originally Posted by koei

I mean I installed NVStrap, goto the pixel/vertex units configuration and select custom, then change the disabled units to enable. After that's done, it showed under NVStrap that I selected the 24x1 and 8x1 configuration, but after reboot, it still shows 20x1 7x1 under main menu of RivaTuner and benchmark shows the same performance results.

Ahh... that's the same as what others say. Do you have to reboot to get it to work?

[koei]

Yes, it asks you to reboot after making the change to the masks.

[zippyc]

Thanks for the great info Cooper.

I have a new PNY 7800GT that clocked fine on standard volts from 400 to 504 at the core (so I'm guessing the other pixel clock speeds were much higher as your chart indicates.)

I'm very pleased with a 104Mhz overclock, but my temp probe shows that highest GPU temps are only 111F/43.8C.

This leads me to believe I've plenty of headroom for overclocking yet, and just need to get more volts to the GPU.

Anyone here know of a volt mod for the 7800GT GPU? I've asked this on a couple other threads, no answers yet....

[Cooper]

zippyc maybe you could overvolt the core with nibitor - softvoltmod ?
I`m trying to overvolt mine 6800 for 0.1 V. It`s actually very easy. Just remeber to save your curent BIOS if something goes wrong.

[Ackbar]

Originally Posted by zippyc

Thanks for the great info Cooper.

I have a new PNY 7800GT that clocked fine on standard volts from 400 to 504 at the core (so I'm guessing the other pixel clock speeds were much higher as your chart indicates.)

I'm very pleased with a 104Mhz overclock, but my temp probe shows that highest GPU temps are only 111F/43.8C.

This leads me to believe I've plenty of headroom for overclocking yet, and just need to get more volts to the GPU.

Anyone here know of a volt mod for the 7800GT GPU? I've asked this on a couple other threads, no answers yet....

Holy... that's a really nice overclock for a 7800GT! I can only get to ~475/1200. I noticed that the memory bandwidth is really key though. I think I was lucky to get a card that does both pretty well and not just one or the other. NiBiTor will not work, the voltage tables are already maxed out on there cards (7800GT/GTX).

[Cooper]

Acbar. Well i think you just have to encrese the voltages yourself by tweaking the VGA `s BIOS. Or just to try real voltmod.