[Amacapart]

If you want Ti 4600 figured out, someone needs to get me hi-res pix with resolution good enough to read #'s on board and resistor positions.

http://www.amacapart.com/images/xtres.jpg

[traktimino]

a couple of questions,

couldn't it just be flashed with the reduced 9800 rom so the resistor mod and chip swap would be unecessary?

are all 256 mb vram recognized and utilized?

[Amacapart]

Check at XLR8 forums. Lord Vader has the 1st card I did.

It appears there is thermal sensing circuitry, etc in new XT ROM.

Allows all 256 Megs and runs fan at different speeds.

Reduced ROM has not been done for this ROM yet. Plus, in reduced ROM for 9800 pro you do lose some res and the startup power-on/off message. Likely that this thermal sensing stuff might not make it into reduced ROm if someone does decide to do it.

Oh, and to all the people who called me a lying sack of crap in this thread many moons ago:

http://forums.macnn.com/showthread.p...hreadid=215611

I am now accepting apologies.

If the XLR8 posts don't convince you, read up at Macbidouille. The Great Rorqual has now replicated my work, and linked to it.

[hpence]

brilliant work and discovery dave. You and Rorqual brought us back to the fastest ATI card for the mac.

I'm a little disapointed at the lack of enthusiasm in these forums. You'd figure people would have a few questions, comments, or at least offer a congrats for the breakthrough after the hours of work to get there. I'm sure it'll save several of them a LOT of money when they go to upgrade.

Now, my question comes as this: Do the 9800's with an R350 core perform the same clock per clock as one with an R360 core?

Im wondering because of possible difficulties in verifying that all 256mb are seen AND being used. The only way to know for sure is to bench this 256mb card vs a 128mb card with the same clock settings. Might be hard to get a 128mb card with a 360core if the perfomance clock/clock is >.01% differece.

System profiler is accurate 95% of the time, it was wrong when a 128mb 9800pro was flashed with the updated 9800 mac SE rom.

[Amacapart]

Thanks for kind words.

9800 XT is FASTEST CARD FOR A G4. I stsated this in June and now this is finally becoming accepted fact. I now know how difficult Christopher Columbus had it trying to prove his wacky "earth is round" theory. Now that it is being written about on Macbidouille AND XLR8 there is no more doubting me.

It is worrisome that Sys Profiler doesn't seem as accurate as before. I don't know why.

Biggest advantage with current apps is faster components. R360 runs faster than R350. The RAM on an XT is rated for 400 Mhz while 9800 Pro is only 350 Mhz. Current games can't really use the 256 to their advantage. The card will be VERY useful when Doom 3 comes out.

Sadly, I had to send out the first card I did. I have done another for someone else and have been asked to do more. As Doom 3 gets closer I think interest will pick up. Also as people realize how pathetic their 8500/9000's are for 10.4/Coreimage there will be a move to dump the "pig with lipstick" and move to a more modern card capable of running the newer apps.

Doom 3 will finally be able to use this RAM to good effect. A good way to test today though is with Halo. I had an 8500 with 128 Megs of RAM. It flashed fine and ran fine UNTIL it tried to access the RAM beyond 64 megs, where it would crash. This was due to Mac ROM and drivers only being written for 64 Megs. But it was very hard to get it to crash, Halo was only app I could do this with. Curiously, all 128 showed up in ASP. Same with the Radeon 7000 64 Megs cards. Ram is there and used properly though these didn't have crashing issue despite original ROM and drivers being written with just 32 Megs in mind.

So why the 128 Meg 9800s can think they have 256 megs is odd. I imagine if they tried maxed out details and lens flare set to high in Halo they MIGHT be able to crash system when it tries to access this non-existent memory

Nvidia GF3 Ti 200's sometimes had 128 Megs. When flashed with Mac ROM they ran at 64 megs, no issues. It would seem the Nvidia RAM use was a little tidier.

[hpence]

Dont know about the nvidia hypothesis. Any card should be able to work if its flashed with a usable ROM that addresses less memory. Easy way to test this would be to flash a 128mb 9000 with the 64mb rom. Its just a 1 bit difference in the number of address locations.... (unless they upped the addressability [size of each memory location], but if thats the case i dont think the ROM would run at all on the cards)

If the ROM tried to put a line into memory that did not exist, either the card would crash right then, or crash when it was trying to be accessed. --- but then again the ROM might take in account for this/other corruptions and go back to accessing through the AGP bus if anything goes janky in a certain memory location.

All in all - hard so say how they really behave until we can interpret the ROM code.

Only way to know for sure if all 256mb of the XT is used is to benchmark a r360 core 9800pro with 128mb (or loaded with a 128mb ROM) clocked the same as an XT.

[lenox]

Awesome work, Amacapart!

Don't let the doubters get you down; they're just used to being sour about mac video cards and gaming. It's kind of understandable

[SamuraiDL]

wow, going to school over here...