The additional features tab

RBE offers you some more. Maybe you don't want to tinker with the PowerPlay settings to overclock your card (even if it's easier than you think, trust me). Overclocking using the Overdrive functionality of the Catalyst Control Center (CCC) is comfortable but has some disadvantages:

• PowerPlay and its power saving features are completely turned off then
• Fan control won't work any more. You can program a certain fan duty using the CCC profile editor (see section 3.6), but it's not dynamic
• The overclocking headroom is limited to a maximum value

At least for the last disadvantage RBE offers a solution. At the beginning of this tutorial there was a digital signature mentioned protecting several settings inside the BIOS. This is mostly for protecting the Overdrive limit. You know, ATI makes a reference design of the card. Vendors can build cards referring to that design or designing a new layout, maybe with more powerful voltage tranformers and cooling.
As such, they maybe want to overclock the card more in order to have an advantage over other vendors when it comes to selling cards for profitable prices. To protect the customers from vendors playing around too much with that, ATI invented a mechanism of protecting the clocks.

The vendor builds a card and then needs a BIOS for it, of course. He makes one using a tool from ATI for that, but the BIOS built this way isn't usable yet. It needs to be sent to ATI. Guys there look into the clocks and some other things and if everything is as they like it, they add a digital signature to the BIOS and send it back to the vendor. This signature locks the default and Overdrive clock rates and therefore, vendors can't make extremely high overclocked BIOSes without ATI knowing and approving (and maybe being payed for).

RBE now offers two methods on bypassing this:

1. Transplanting the concerned sections from an overclocked BIOS to another BIOS, including the digital signature, and
2. Changing the Overdrive headroom regardless the signature (some people report this works).
   

On loading a BIOS file, RBE automatically determines if there is data for using method one. If so, it offers them in this additional features tab:

• Selecting "Method 1 - Hash", "change to these values" there and saving the BIOS will overwrite the BIOS' Overdrive settings (if you want to call them that way) displayed on the left (Actual settings) with the increased ones on the right.
  *Caution*: Here you see an example of a 4870. You may want to change the pull down menu to the 3870 values as they are even higher. You shouldn't do that! Those settings include the device ID (that's why you were asked not to change the device ID in section 3.2). Running a 4870 which reports to Catalyst as being a 3870 is not a good idea, as you can imagine.

• Method 2 is - to be honest - not very likely to work. It simply increases the Overdrive limit inside the BIOS no matter what. After this, your BIOS' digital signature will not match any more (don't get this mixed up with the checksum mentioned in section 3.2 - this will be in good shape however).
  Some people on the Internet claim this works regarding several Catalyst versions, but this is not certified yet. You can try to edit your BIOS that way, but have the original BIOS ready if it fails.
  Simply click on the "Method 2 - No hash" option button and move the sliders to or enter the values you like.

In order to use the method one Overdrive hack, you can also load and save decent signature files. Consider you are using a 4850. Your maximum Overdrive headroom might be 700 MHz for the GPU. The maximum Overdrive increase signature that is saved in RBE might be 720 MHz. Now you found a BIOS that's maximum Overdrive is 750 MHz. So you can load this BIOS into RBE and save its Overdrive signature off that BIOS to your hard disk using the "Save..." button right at top of the actual settings frame. Specify a location and a file name in the window that just pops up to save the BIOS' signature. After that, you can load your card's original BIOS and, afterwards, load the signature you just saved using the "Load..." button. As you can see, the combo box shows "Custom" now and the Overdrive settings of your signature are listed in the "Increased values" frame. Saving your BIOS using these signature values will get the job done. Flash this BIOS to your card, reboot and use Overdrive for overclocking up to 750 MHz!
You can distribute the signature you extracted for other users to benefit from it here. You can also browse this thread for interesting signatures for you to use.

There are even more things for you:
Several 4870 cards have been reported to have a "spin up bug", as I call it. This bug causes the fan to spin up to almost 100% at certain conditions, stay there for a couple of seconds and drop down again, no temperature issue given. RBE automatically determines if the loaded BIOS contains the bug and offers to fix it. If this option is greyed out for you, your BIOS doesn't sufffer from that bug.

For several BIOSes, RBE can unlock superior PowerPlay functionality, saving even more power in low load modes. Additionally, it can decrease several voltages to more recommended values having the superior PowerPlay applied. It simply sets some voltages in the clock settings tab to lower values, you can convince yourself what's going on here by loading a BIOS modified that way into RBE again.
Again, RBE determines by itself if the option can be offered and if not, the option is greyed out.