Introduction

ATI's X800 Pro, X800 Pro VIVO and X800 XT PE cards are all based on the same GPU Chip - the R420. As you all know the Pro series has 12 rendering pipelines while the XT series has 16. It wouldn't be cost effective to make two versions of the R420 chip, so ATI is disabling 4 pipelines on the chip after production, just like on R300 and R350 before.

On the R3X0 cores ATI used a resistor - on R420 a laser cut as shown in the following picture:


X800 Pro VIVO cores do not have the laser cut:


The X850 Pro VIVO can be modded the same way, you just need another Bios.

It is still running with only 12 Pipelines, even after flashing an XT Bios to it. The reason why the XT Bios does not unlock the additional pipelines can be found in the Flashrom flashing tool. It "preserves" certain ROM Bios settings when flashing another BIOS:


Several people have used a Gigabyte Bios and flashing tool to get around this, but for some reason you can not flash back to 12 pipelines with this method- if you have defective pipelines you keep them.

The method I present here uses a modified flashrom which does not preserve Bios settings.
This allows:

• flashing of any Bios
• going back to 12 Pipelines
• can not be detected

It will only work on the X800 Pro VIVO and X850 Pro VIVO. Manufacturer does not matter. It will not work on any non-VIVO cards.

The modified flashrom has been updated on Jan 03 2005 to support both AGP and PCI-Express X800 Pro VIVO cards. The mod is the same, just get a X800 XT PE PCI-E BIOS when flashing a PCI-E card.

If you flash a PCI-E Pro VIVO and the card is detected as "X800 SE" after flashing, you flashed the wrong BIOS.

Instead of the modified flashrom you can also use ATI's atiflash 3.xx. Just add -newbios to the command-line switches to disable "Preserve BIOS settings".

Rumor has it that Gigabyte X800 Pro VIVOs come with activated 16 pipelines out of the box.


All VIVO cards can be identified by this yellow CD-Audio connector near the power plug. If your card has not got this connector, it is not VIVO and can not be modded.

Performing the Mod

1. Download modified flashrom.
2. Download Bios from here.
   I suggest the latest X800XT PE Bios (or X850 XT Bios if you are modding an X850 Pro VIVO).
   A little sidenote: Many people complain that they get a "file not found" error when trying to flash the bios under DOS. The problem is that DOS does not know long filenames, so all files are truncated to some funky names like Powerco~1.bin. Either use the dir command, when in DOS, to find out the short filename or rename the file to something shorter while still in Windows.
3. Make sure the card can reliably run at the clock speeds of the new bios (with ATITool, for example).
   If you know your card can't handle the XT PE speeds you can download a modified X800 Pro VIVO Bios from the Bios Collection as well (ATI X800 Pro VIVO 16P). This bios is just 16P enabled and is detected as X800 Pro by the drivers - clocks are unchanged.
4. Make a backup of the existing Bios of your card. Yes, make a backup, do not rely on the Bios collection. The reason is that different pipelines could be disabled on your card than in the Bios from the collection. So if you want to flash back because of artifacts, the Bios from the collection might disable the working pipelines and leave you running with the bad ones.
5. Use the modified flashrom to flash the Bios to the card. More extensive flashing instructions can be found here. They talk about atiflash - you use the modified flashrom, usage is the same.
6. After bootup Windows should automatically install the X800 XT PE driver.
7. Verify the number of active pipelines using ATITool. Go to Settings -> Overclocking. The list there shows the number of pipelines the card is running with.
   

You can use this CD ISO Image (1.5 MB) to flash the 16P modded X800 Pro VIVO AGP BIOS to your card. After starting from the CD, a boot menu comes up. Please make sure you already have made a backup of your existing BIOS at this point.

If you want to remove all traces of previous Bios flashes (for example if you flashed the Gigabyte Bios):
Use modified flashrom to flash empty.bin (use "Save as..." if weird characters appear when clicking the link) to your video card, then flash the new Bios without rebooting. Be careful - if you don't flash a real Bios after flashing the empty Bios, your card will not work properly.