I'm using a Gigabyte R955 (128 bit).

Max OC at 400 Core, 480Mhz Mem with stock passive cooler. This is just a conservative setting to reduce damage risk.

3DMark 2001 SE score:
10,132 @ 1.800GHz and 400,480
11,188 @ 2.255GHz and 400,480

3DMark 2003 score:
3,059 @ 2.00GHz and 350,440

Aquamark 3:
27,884 @ 2.277GHz and 400,480

edit: added Aquamark 3 score

This post has been edited by rcky: Feb 24 2006, 12:09 PM

Maybe it's got something to do with the core cooler. Even my crappy (and I mean cheap, lame-@$$ looking crappy) passive unit can do 400 with no problems (although I'm always on the worry whether it'll burn out or not).

Might I suggest that you get an aftermarket cooler like the CoolVIVA? I just got one for myself but I'm yet to install it. I'm pretty sure it can hit at least 450 once it's done. I'll post up some pics and results after installing it.

I got it for only RM40 from kevinn7 in the Bulk section (together with a pack of RAMsinks for the VGA's RAM).
As for the mem speed, I'm very intrigued by the article written by Shah81. I'd like to try out the mem timing tips once I mod my 9550. Maybe that would help. 9550-->9550 GT spec would be enough for me.

As we speak, I've just finished slapping on my CoolVIVA on my 9550. Here are the results:

No artifacts at 470Mhz Core, 500MHz Mem, default voltage and RAM timings. I'm very happy, to say the least.

I'll post up some pics tomorrow of my 9550 and after it has been installed in the PC, including my review of the CoolVIVA. Hope it could be helpful to those planning on buying a cooler for their 9550.