DISCLAIMER: I will not take responsibility should you damage or burn out your card.
Many of you probably have the Gecube 9550XT Extreme Edition. For RM 390 it's quite a deal, because of it's near on par, if not, greater than the 9600 Pro performance. Since revision 1.0 all the way to 2.0, we have been hearing good oc results, especially for those with Hynix 2.5ns rams. But there have been only few that have succesfully overclocked the Rev 2.1. Why? I actually have no damn idea, but what i do know, is how to overlcok it succesfully. The biggest factor on the Rev 2.1 is the unoverclockability of the core, which defaults to 432 mhz. Most of whom i have heard can only oc this to 440max, with lockups anything over it. Initially I thought of a bios lock, because the 9550XT was so popular, it kept people from buying a 9600 Pro/XT. However after flashing the bios with many different versions of the 9600, I have noticed that the core remains unoverclockable, but the memory soars, so it may be a good idea to keep a 9600 Pro bios on it, more on that later.
Alas, with help of rx8, a relatively new member to this forum, we have found out where to volt mod the core and the memory.
The voltage regulator chip is an ON 1571. It's brand name was not written on it, so it took forever to find results on google and the datasheet, but after page 25 or so on google, I found it. The other problem was finding the memory voltage. It was easy to find the core voltage, which is the pin of the coil for the core. However, for the memory, the coil was rated at 1.92v. Pretty strange for DDR memory? Yes, I agree, and I personally doubt it's got gDDR3 on it, and unfortunately, I can't find out either, since I have ramsinks superglued to the mem chips. If one of you could write down the code, and post it here, I would very much appreciate it.
Alas, after simply appyling the same voltage mod on the memory as on the core (because they both have the same regulator chips, 1571), my memory was more overclockable, so I thought, what the heck, as long as it runs higher, I wasn't gonna complain. But be assured, I'm not 100% sure, that the memory mod below will actually increase mem speed, unless I know wether i got gDDR1 or gDDR3.
Ok, so I'm done talking pure, useless crap, here's the mod:
:::vGPU & vDDR Mod:::
Simply draw a pencil line at those two ] to increase coltage. Check the voltage after every pencil line though. You don't want to shoot up the volts to 2v or smth like that.
If you don't like Pencil Modding, you can simply solder a 10K Pot to Pin 7 and to the ground.
Initially my core voltage was at 1.32v and memory at 1.92 at the max OC of 435/306 to 1.71v/2.2v at 532/336. This is with stock 9550 bios, not with 9600 Pro bios, so if I flash sooner or later, my mem will fly even higher.
Happy Modding,
Regards,
Dead__Man with help of rx8
This post has been edited by Dead__Man: Apr 11 2005, 03:34 PM
Voltmodding Gecube 9550 Rev2.1, This is not a question, but a guide!