Hey all! Haven't posted in awhile, but this caught my attention. I also have the Hercules Prophet II GTS Pro 64, and I love it (Only had Voodoo cards up until this point)!
Anyway, I currently have my Vid card at: Core: 220, Mem: 433
I'm using the default cooling fan/heat sink that came on the card, but I do have a blow fan that sits in a slot (doesn't actually plug into the slot though) next to the vid card and sucks air away from card and out the back of my pc. I threw the packaging away for it, but I did get it from Compusa (maybe Antec was the brand?) for about 20 bucks.
Even if I underclock the core, I still can't get past 433 for the mem (overclocking mem is more important since that's the bottle neck usually....for all those who didn't already know that🙂
Right now I'm running a T-Bird 900 at 1.1 Ghz @ 1.775 V (changed multiplier to 10, and FSB to 110) with out any "active" cooling (I added a couple more fans to the case along with drilling some holes in various places....wife really liked me doing that in the family room 🙂 ) on an MSI K7T Pro2a m.b.
The reason I'm telling you this is because I used to be able to run the actual core of the vid card at 235 (with mem still at 433) when I had the my rig at 1.1 GHz using a 10.5 multiplier and FSB of 105 (but I needed to increase the V to 1.85 which I didn't like doing).
I have no idea why it won't do the same now...if anything I thought reducing the FSB speed would make it easier on the vid card and I would be able to overclock it even more...guess not though.
Anyway, if you don't want to buy any fans and you have an old case fan laying around you might want to try having it blow over the Back of the card and out the back of case. I mean the side without the heatsink/fan when I say back. Try touching the back of the card after running for awhile....gets WAY hot. That helped me out until I got this other fan from Compusa.
Even if you can't overclock it at all the card still rocks though!!! 🙂
Good Luck